Oxygen-absorbing resin composition

ABSTRACT

Provided is a resin composition which is excellent in an oxygen-absorbing performance, a resin strength and a resin processability. 
     The oxygen-absorbing resin composition is characterized by containing a polyolefin resin, a transition metal catalyst and a polyamide resin obtained by polycondensation of aromatic diamine and dicarboxylic acid, wherein an end amino group concentration of the above polyamide resin is 30 μeq/g or less, and a total content of the transition metal catalyst and the polyamide resin is 15 to 60% by weight based on a whole amount of the oxygen-absorbing resin composition.

TECHNICAL FIELD

The present invention relates to an oxygen-absorbing resin compositionwhich shows an excellent oxygen-absorbing performance and which does notcause a reduction in a strength of the resin due to oxidativedegradation and does not generate odor, a production process for anoxygen-absorbing resin composition, an oxygen-absorbing multilayer filmand an oxygen-absorbing multilayer container prepared by thermoformingthe above multilayer film.

BACKGROUND ART

Containers such as metal cans, glass bottles, various plastic packagesand the like have so far been known as packaging containers, and qualitydeterioration caused by oxygen contained in packaging containers hasbeen a problem. Accordingly, it is tried in recent years as one ofdeoxidation packaging technologies to constitute containers from amultilayer material provided with an oxygen-absorbing layer comprisingan oxygen-absorbing resin composition prepared by blending athermoplastic resin with an iron base deoxidizer and the like to try toenhance a gas barriering property of the containers and developpackaging containers in which the containers themselves are providedwith an oxygen-absorbing performance. For example, an oxygen-absorbingmultilayer film is used as a film prepared by providing a conventionalgas barriering multilayer film prepared by laminating a heat sealinglayer and a gas-barriering layer with an oxygen-absorbing layer which isa thermoplastic resin layer dispersed therein with an oxygen absorbentvia an intermediate layer comprising a thermoplastic resin in a certaincase to endow the film with a performance of absorbing oxygen containedin a container as well as a performance of preventing oxygen frompermeating from an outside, and it is produced by making use ofproduction processes which have so far been publicly known, such asextrusion lamination, coextrusion lamination, dry lamination and thelike (refer to a patent document 1).

On the other hand, resin compositions comprising polyamide, particularlyxylylene group-containing polyamide as an oxidizable organic componentand transition metal are known as compositions comprising polymers andhaving an oxygen-scavenging characteristic, and shown are the examplesof resin compositions having an oxygen-scavenging performance and oxygenabsorbents, packaging materials and multilayer laminated films forpackaging which are obtained by molding the above resin compositions(refer to patent documents 2 to 8). Further, known as well aretechnologies in which the above oxygen-absorbing multilayer films areused for a cover material of a barriering container to tightly seal thebarriering container to thereby prevent oxidative deterioration of acontent thereof.

However, problems such as detection by a metal detector used fordetecting foreign matters in foods and the like, deficiency of an insidevisibility due to a problem of opacity and incapability of use thereoffor beverages such as alcohols and the like which are damaged in aflavor by mixing of iron powder have been involved in compositions inwhich an oxygen absorbent such as iron powder and the like is used.Further, oxidation reaction of iron powder is used, and therefore aneffect of absorbing oxygen can be exerted only on stored films having ahigh moisture.

On the other hand, in resin compositions which contain a transitionmetal catalyst and in which a polyamide resin is oxidized to exert anoxygen-absorbing performance, a xylylene group-containing polyamideresin is oxidized, and therefore involved therein is the problem thatthe resin is reduced in a strength due to oxidative deterioration toallow the packaging container itself to be reduced in a strength.

MXD6 which is polyamide obtained by polycondensation ofmetaxylylenediamine and adipic acid is shown as an example in whichoxidation reaction is exerted by a polyamide resin and a transitionmetal catalyst. However, in a system in which MXD6 is mixed withtransition metal, an oxygen-absorbing ability is so low in a certaincase as to use it as an oxygen-absorbing resin composition to store wella stored film. Also, the viscosity is reduced due to oxidativedecomposition of MXD6 in mixing with the transition metal, and a problemof a reduction in the processability has been involved therein. Further,in a system in which MXD6 is mixed with transition metal, a blend with apolyester resin such as polyethylene terephthalate (hereinafter shown asPET) and the like and a resin having a relatively high melting pointsuch as nylon 6 and the like has so far been usually used.

Also, a fluid infusion container in which a liquid chemical is a contentis used by connecting it directly with a tube and the like, andtherefore it is handled in a state in which it is put in an exteriorpacking material comprising a synthetic resin film in order to preventthe container from being contaminated before actually used. A fluidinfusion container is constituted from a resin which permeates oxygen interms of a sanitation and the like, and therefore the exterior packingmaterial has to have a gas barriering property in order to prevent acontent fluid thereof from being changed in a quality by oxygen.However, oxygen is present more or less in an exterior packing materialafter tightly sealed, and the fluid content has to be prevented frombeing changed in a quality by oxygen which permeates as time passes evenif a gas-barriering exterior packing material is used. Accordingly, acontent fluid of a fluid infusion container has so far been preventedfrom being changed in a quality not only by charging an exterior packingmaterial with the fluid infusion container at a low oxygen concentrationbut also by putting an oxygen absorbent together with the fluid infusioncontainer in the exterior packing material to absorb remaining oxygenand permeating oxygen by the above oxygen absorbent to thereby maintainan amount of oxygen in the exterior packing material at a low level(refer to the patent document 1).

However, in resin compositions which contain a transition metal catalystand in which a polyamide resin and the like are oxidized to exert anoxygen-absorbing performance, a xylylene group-containing polyamideresin is oxidized, and therefore involved therein is the problem thatthe resin is reduced in a strength due to oxidative deterioration toallow the packaging container itself to be reduced in a strength.

CITATION LIST Patent Document

-   Patent document 1: Japanese Patent Application Laid-Open No.    234832/1997-   Patent document 2: Japanese Patent Application Laid-Open No.    140555/1993-   Patent document 3: Japanese Patent Application Laid-Open No.    252560/2001-   Patent document 4: Japanese Patent Application Laid-Open No.    341747/2003-   Patent document 5: Japanese Patent Application Laid-Open No.    119693/2005-   Patent document 6: Japanese Patent Application Laid-Open No.    179090/2001-   Patent document 7: Japanese Patent Application Laid-Open No.    256208/2002-   Patent document 8: Japanese Patent Publication No. 33632/1993

SUMMARY OF INVENTION Problem to be Solved by the Invention

An object of the present invention is to provide a resin compositionwhich is excellent in an oxygen-absorbing performance, a resin strengthand a resin processability and a production process for the aboveoxygen-absorbing resin composition.

An object of the present invention is to provide an oxygen-absorbingmultilayer film which is excellent in an oxygen-absorbing performance, aresin strength, a resin processability and an appearance and in which acontent is visible and an oxygen-absorbing multilayer container.

An object of the present invention is to provide an oxygen-absorbingmultilayer film which is excellent in an oxygen-absorbing performance, aresin strength, an interlayer strength between an oxygen-absorbing layerand a gas-barriering layer and a resin processability and anoxygen-absorbing multilayer container.

An object of the present invention is to provide a method for preservinga content of a fluid infusion container by using an oxygen-absorbingmultilayer film in which a content of a fluid infusion container can bepreserved for a long time without deteriorating the content and whichhas a transparency

Means for Solving the Problem

The present inventors have found that an oxygen-absorbing resincomposition which is excellent in an oxygen-absorbing performance andmaintains a resin strength after stored and which is excellent in aresin processability, a production process for the same, anoxygen-absorbing multilayer film prepared by using the aboveoxygen-absorbing resin composition and an oxygen-absorbing multilayercontainer are obtained by blending specific polyamide and transitionmetal with a polyolefin resin in a specific proportion.

That is, the present invention relates to:

[1] an oxygen-absorbing resin composition containing a polyolefin resin,a transition metal catalyst and a polyamide resin obtained bypolycondensation of aromatic diamine and dicarboxylic acid, wherein anend amino group concentration of the above polyamide resin is 30 μeq/gor less, and a total content of the transition metal catalyst and thepolyamide resin is 15 to 60% by weight based on a whole amount of theoxygen-absorbing resin composition,[2] an oxygen-absorbing multilayer film comprising at least three layersof a sealant layer comprising a thermoplastic resin, an oxygen-absorbingresin layer containing a polyolefin resin, a transition metal catalystand a polyamide resin and a gas-barriering layer comprising agas-barriering film, wherein the above polyamide resin is a polyamideresin which is obtained by polycondensation of aromatic diamine anddicarboxylic acid and in which an end amino group concentration is 30μeq/g or less, and a total content of the transition metal catalyst andthe polyamide resin in the oxygen-absorbing resin layer is 15 to 60% byweight,[3] a production process for the oxygen-absorbing resin compositionaccording to the above item [1] in which a content of the transitionmetal is 200 to 5000 ppm based on the polyolefin resin, wherein a masterbatch containing the polyolefin resin and the transition metal catalystis molten and kneaded with the polyamide resin,[4] an oxygen-absorbing multilayer container prepared by thermoformingthe oxygen-absorbing multilayer film according to the above item [2],[5] an oxygen-absorbing multilayer container prepared by subjecting alaminated material prepared by laminating at least a paper substrate, agas-barriering layer, the oxygen-absorbing resin layer according to theabove item [2] and a thermoplastic resin inner layer in this order toplate working and[6] a method for preserving a content of a fluid infusion container inwhich a content of a fluid infusion container is preserved in anoxygen-absorbing container prepared by using wholly or partially anoxygen-absorbing multilayer film prepared by laminating at least threelayers of an oxygen-permeating layer comprising a thermoplastic resin,an oxygen-absorbing resin layer containing at least a polyolefin resin,a transition metal catalyst and a polyamide resin and a gas-barrieringlayer comprising a gas-barriering film in order from an inside, whereinthe above polyamide resin is a polyamide resin which is obtained bypolycondensation of at least aromatic diamine and dicarboxylic acid andin which an end amino group concentration is 30 μeq/g or less, and atotal content of the transition metal catalyst and the polyamide resinin the oxygen-absorbing resin layer is 15 to 60% by weight.

Advantageous Effects of the Invention

According to the present invention, capable of being provided are anoxygen-absorbing resin composition which has a high oxygen-absorbingperformance and which is scarcely observed to be deteriorated in astrength by oxidation of a polyamide resin and a production process forthe above oxygen-absorbing resin composition.

According to the present invention, capable of being provided is anoxygen-absorbing resin composition which has a high oxygen-absorbingperformance and a high molding processability and which is scarcelyobserved to be deteriorated in a strength by oxidation of a polyamideresin.

According to the present invention, capable of being provided are anoxygen-absorbing multilayer film which has a high oxygen-absorbingperformance, a high molding processability and a transparency and whichis scarcely observed to be deteriorated in a strength by oxidation of apolyamide resin and an oxygen-absorbing multilayer container.

According to the present invention, capable of being provided anoxygen-absorbing multilayer container which has a high oxygen-absorbingperformance and is scarcely observed to be deteriorated in a strength byoxidation of a polyamide resin and which is excellent in aprocessability and a storing property of a stored film.

According to the present invention, capable of being provided a methodfor preserving a content of a fluid infusion container by using anoxygen-absorbing multilayer container which has a high oxygen-absorbingperformance and is scarcely observed to be deteriorated in a strength byoxidation of a polyamide resin and which has a visibility of a content.In addition thereto, the above method makes it possible to store acontent of a fluid infusion container for a long time without causingdeterioration thereof.

EMBODIMENTS FOR CARRYING OUT THE INVENTION Oxygen-Absorbing ResinComposition:

The oxygen-absorbing resin composition of the present invention is anoxygen-absorbing resin composition containing a polyolefin resin, atransition metal catalyst and a polyamide resin obtained bypolycondensation of aromatic diamine and dicarboxylic acid, wherein anend amino group concentration in the above polyamide resin is 30 μeq/gor less, and a total content of the transition metal catalyst and thepolyamide resin is 15 to 60% by weight based on a whole amount of theoxygen-absorbing resin composition.

Polyamide Resin A:

An oxygen-absorbing performance of the oxygen-absorbing resincomposition is considered to be better in the oxygen-absorbing resincomposition containing a larger amount of the polyamide resin to whichtransition metal having an oxygen-absorbing ability is added, but to besurprised, it has been found that a high oxygen-absorbing ability isshown when the polyamide resin and the transition metal are mixed andblended with the polyolefin resin in a fixed proportion.

The polyamide resin in the present invention is obtained bypolycondensation of aromatic diamine and dicarboxylic acid and has anend amino group concentration of 30 μeq/g or less (hereinafter referredto as “the polyamide resin A”). The polycondensation of aromatic diamineand dicarboxylic acid can be allowed to proceed by melt polymerizationin which aromatic diamine and dicarboxylic acid are molted and solidphase polymerization in which pellets of a polyamide resin are heatedunder reduced pressure.

In the present invention, the aromatic diamine used in preparing thepolyamide resin A includes orthoxylylenediamine, paraxylylenediamine andmetaxylylenediamine, and at least one selected from metaxylylenediamineand paraxylylenediamine is preferably used from the viewpoint of theoxygen-absorbing performance. Metaxylylenediamine is more preferablyused. A mixture of metaxylylenediamine and paraxylylenediamine ispreferably used as well. Further, various aliphatic diamines andaromatic diamines may be incorporated thereinto as copolymerizingcomponents as long as an influence is not exerted on the performances. Acontent proportion (mol %) of the respective components in mixingparaxylylenediamine and metaxylylenediamine is preferablyparaxylylenediamine:metaxylylenediamine=20 to 60:80 to 40, particularlypreferably 25 to 50:75 to 50.

The dicarboxylic acid includes adipic acid, sebacic acid, dodecanoicdiacid, isophthalic acid, malonic acid and the like. Among them, atleast one selected from adipic acid, sebacic acid and isophthalic acidis preferred from the viewpoint of the oxygen-absorbing performance.Further, various aliphatic dicarboxylic acids and aromatic dicarboxylicacids may be incorporated thereinto as copolymerizing components as longas an influence is not exerted on the performances. A polycondensationproduct of paraxylylenediamine, metaxylylenediamine or a mixture thereofwith a mixture of adipic acid and sebacic acid or with a mixture ofadipic acid and isophthalic acid is more preferably used for thepolyamide resin A.

In the present invention, the dicarboxylic acid described above containspreferably adipic acid and sebacic acid in a proportion of preferably3/7 to 7/3, more preferably 4/6 to 6/4 in terms of a mole ratio (adipicacid/sebacic acid) from the viewpoint of the oxygen-absorbingperformance, and the aromatic diamine contains preferablymetaxylylenediamine in a proportion of preferably 0.985 to 0.997, morepreferably 0.990 to 0.995 based on 1 mole of the dicarboxylic acid. Fromthe same viewpoint, a mole ratio in carrying out the polycondensation ofthe diamine described above with adipic acid and sebacic acid isdiamine:sebacic acid:adipic acid=preferably 0.985 to 0.997:0.3 to0.7:0.7 to 0.3, particularly preferably 0.988 to 0.995:0.4 to 0.6:0.6 to0.4. Also, a mole ratio in carrying out the polycondensation of thediamine such as metaxylylenediamine with adipic acid and isophthalicacid is diamine:adipic acid:isophthalic acid=preferably 0.985 to0.997:0.70 to 0.97:0.30 to 0.03, more preferably 0.988 to 0.995:0.80 to0.95:0.20 to 0.05.

The polyamide resin A in the present invention is a polyamide resinwhich is obtained by polycondensation of aromatic diamine anddicarboxylic acid and which has an end amino group concentration of 30μeq/g or less. If the end amino group concentration is 25 μeq/g or less,the oxygen-absorbing performance is enhanced, and therefore it ispreferred. If it is 20 μeq/g or less, the oxygen-absorbing performanceis further enhanced, and therefore it is more preferred. As shown above,the oxygen-absorbing performance tends to be enhanced as the end aminogroup concentration is reduced, and the above concentration ispreferably reduced as much as possible. However, considering theeconomical rationality, a lower limit value thereof is preferably 5μeq/g or more. If the end amino group concentration is higher than 30μeq/g, the good oxygen-absorbing performance can not be obtained.

In order to control an end amino group concentration of the polyamideresin to 30 μeq/g or less, preferably carried out are methods such as:

1) a method in which a mole ratio of aromatic diamine to dicarboxylicacid is controlled to carry out polycondensation,2) a method in which the polyamide resin is reacted with carboxylic acidto mask an end amino group and3) a method in which the polyamide resin is subjected to solid phasepolymerization.

The above methods can be carried out alone or in combination. Inparticular, if the methods 1) and 3) and the methods 2) and 3) arecarried out in combination, the polyamide resin which is more excellentin an oxygen-absorbing performance and a moldability in preparing thefilm is obtained, and therefore it is preferred. The above methods shallbe explained below.

In 1) the method in which a mole ratio of aromatic diamine todicarboxylic acid is controlled to carry out polycondensation, thedicarboxylic acid is used excessively to the aromatic diamine, and to bespecific, a mole ratio (aromatic diamine/dicarboxylic acid) of thearomatic diamine to the dicarboxylic acid is preferably 0.985 to 0.997,particularly preferably 0.988 to 0.995. If the above mole ratio is lessthan 0.985, a polymerization degree of the polyamide resin is lessliable to be elevated in a certain case, and therefore it is notpreferred.

In 2) the method in which the polyamide resin is reacted with carboxylicacid to mask an end amino group, an end amino group of the polyamideresin is reacted with carboxylic acid to control an end amino groupconcentration. That is, in the present invention, the polyamide resin ispreferably masked at an end by carboxylic acid to control an end aminogroup concentration to 30 μeq/g or less. Compounds having at least onecarboxyl group and in addition thereto, anhydrides thereof are includedin the carboxylic acid used in the present invention, and they are usedas end masking agents for an end amino group of the polyamide resin.

In the present invention, end masking means that an end amino groupconcentration is reduced by reacting an end amino group of the polyamideresin with carboxylic acid to form an amide bond. The carboxylic acidused shall not specifically be restricted, and carboxylic anhydride ispreferred in terms of a high reactivity thereof. To be specific, capableof being shown as the examples thereof are phthalic anhydride, maleicanhydride, succinic anhydride, hexahydrophthalic anhydride, benzoicanhydride, propionic anhydride, caproic anhydride, glutaric anhydride,itaconic anhydride, citraconic anhydride, acetic anhydride, butyricanhydride, isobutyric anhydride, trimellitic anhydride, pyromelliticanhydride and the like. Further, the polyamide resin can be reacted withthe carboxylic acid, for example, by a method in which they are added inmelt polymerization and a method in which the carboxylic acid is addedto the polyamide resin obtained by melt polymerization and in which theyare then molten and kneaded. Among them, melting and kneading ispreferred because of the reason that a polymerization degree of thepolyamide resin can be elevated.

An addition amount of the carboxylic acid described above is, to betheoretical, suitably an amount equal to an end amino groupconcentration in the polyamide resin. In general, it is varied accordingto a volatility and a reactivity of the carboxylic acid, and added ispreferably 0.2 to 5.0 equivalent thereof, more preferably 0.5 to 3.5equivalent thereof based on an end amino group concentration present inthe polyamide resin. In the above case, an end amino group concentrationof the polyamide resin A can be reduced as compared with a case in whichthe addition amount deviates from the range described above, and adeterioration in the resin processability due to a reduction in theviscosity and a reduction in the oxygen-absorbing performance can beprevented.

In 3) the method in which the polyamide resin is subjected to solidphase polymerization, the polyamide resin obtained by meltpolymerization is further subjected to solid phase polymerizationreaction to thereby control an end amino group concentration. The solidphase polymerization is allowed to proceed by heating the pellets of thepolyamide resin under reduced pressure. A pressure in the solid phasepolymerization is preferably 100 torr (13.33 kPa) or less, morepreferably 30 torr (4.00 kPa) or less. A temperature in the solid phasepolymerization is required to be 130° C. or higher, preferably 150° C.or higher, and it is preferably lower by 10° C. or higher, morepreferably lower by 15° C. or higher than a melting point of thepolyamide resin. The solid phase polymerization time is preferably 3hours or longer. Carrying out the solid phase polymerization makes itpossible to reduce an end amino group concentration of the polyamideresin and in addition thereto, elevate a molecular weight thereof andcontrol a viscosity thereof.

A polyamide resin having a low crystallinity is preferably used for thepolyamide resin A of the present invention. To be specific, preferred isa polyamide resin which has such a low crystallinity that asemi-crystallization time is 150 seconds or longer and in which a peakof a melting point is not observed in measuring the melting point byDSC. If a semi-crystallization time of the polyamide resin A is 150seconds or longer, the higher oxygen-absorbing performance is obtained.

Considering a processability with the polyolefin resin and anoxygen-absorbing performance, a polyamide resin having a low meltingpoint and a low glass transition temperature (hereinafter shown as Tg)is preferably used for the polyamide resin A. The polyamide resin A hasa melting point of preferably 200° C. or lower, more preferably 190° C.or lower or has particularly preferably no melting point. Tg ispreferably 90° C. or lower, particularly preferably 80° C. or lower.

An oxygen permeability coefficient of the polyamide resin A ispreferably 0.2 to 1.5 cc·mm/(m²·day·atm) (23° C., 60% RH), morepreferably 0.3 to 1.0 cc·mm/(m²·day·atm) (23° C., 60% RH). If the oxygenpermeability coefficient is 0.2 to 1.5 cc·mm/(m²·day·atm) (23° C., 60%RH), the higher oxygen-absorbing performance is obtained when thepolyamide resin A is blended with the polyolefin resin.

Considering a processability in mixing the polyamide resin A with thepolyolefin resin, the polyamide resin A in which a melt flow rate(hereinafter shown as MFR) is 3 to 20 g/10 minutes at 200° C. and 4 to25 g/10 minutes at 240° C. is preferably used. In the above case, if theresin is processed at temperature at which a difference between MFR ofthe polyolefin resin and MFR of the polyamide resin A shows ±20 g/10minutes, preferably ±10 g/10 minutes, the kneading state is improved,and when it is processed into a film and a sheet, the processed productshaving no problems on an appearance can be obtained. MFR of thepolyamide resin A can be controlled, for example, by controlling amolecular weight. A method in which a phosphorus base compound is addedas a polymerization promoting agent and a method in which the polyamideresin A is subjected to solid phase polymerization after meltpolymerization can be shown as the examples of a suitable method forcontrolling the molecular weight. MFR referred to in the presentspecification is, unless otherwise described, MFR of the above resinmeasured at a specific temperature on the condition of a load 2160 g bymeans of an equipment according to JIS K7210, and it is shown by a unitof “g/10 minutes” together with a measuring temperature.

The polyamide resin A can be synthesized by melt polymerization in whicharomatic diamine and dicarboxylic acid are polymerized in a melt stateand solid phase polymerization in which the pellets of the polyamideresin are heated under reduced pressure. In particular, the polyamideresin A is synthesized preferably by a method passing through two stagesof solid phase polymerization after melt polymerization. A numberaverage molecular weight of the polyamide resin A is preferably 18000 ormore, more preferably 19000 or more and further preferably 20000 ormore, and it is preferably 27000 or less, more preferably 26000 or less,more preferably 25000 or less and further preferably 24000 or less. Thatis, a number average molecular weight of the polyamide resin A ispreferably 18000 to 27000, more preferably 19000 to 26000 and furtherpreferably 20000 to 26000.

Polyolefin Resin:

Various polyethylenes such as high density polyethylene, medium densitypolyethylene, low density polyethylene, linear low density polyethylene,ultra low density polyethylene, polyethylene produced by a metallocenecatalyst and the like, polystyrene, polymethylpentene, polypropylenessuch as propylene homopolymers, propylene-ethylene block copolymers,propylene-ethylene random copolymers and the like can be used alone orin combination for the polyolefin resin contained in theoxygen-absorbing resin composition of the present invention. Among theabove polyolefin resins, the resins having an oxygen permeabilitycoefficient of 80 to 200 cc·mm/(m²·day·atm) (23° C., 60% RH) arepreferred from the viewpoint of an oxygen-absorbing performance, andwhen the polyolefin resins having an oxygen permeability coefficientfalling in the above range are used, the good oxygen-absorbingperformance is obtained. Various polyethylenes such as high densitypolyethylene, medium density polyethylene, low density polyethylene,linear low density polyethylene, polyethylene produced by a metallocenecatalyst and the like and various polypropylenes such aspropylene-ethylene block copolymers, propylene-ethylene randomcopolymers and the like are more preferably used as the polyolefin resinin terms of an oxygen-absorbing performance and a film processability.An ethylene-vinyl acetate copolymer, an ethylene-methyl acrylatecopolymer, an ethylene-ethyl acrylate copolymer, an ethylene-acrylicacid copolymer, an ethylene-methacrylic acid copolymer, anethylene-methyl methacrylate copolymer and a thermoplastic elastomer maybe added, if necessary, to the above polyolefin resins.

Considering a mixing property of the polyamide resin A, a maleicanhydride-modified polyolefin resin is preferably added. An additionamount of the maleic anhydride-modified polyolefin resin is preferably 1to 30 wt %, particularly preferably 3 to 15 wt % based on the polyolefinresin.

Also, color pigments such as titanium oxide and the like, additives suchas antioxidants, slipping agents, antistatic agents, stabilizers and thelike, fillers such as calcium carbonate, clay, mica, silica and thelike, deodorants and the like may be added to the polyolefin resin. Inparticular, an antioxidant is preferably added in order to recyclescraps generated during the production and reprocess them.

Transition Metal Catalyst:

The transition metal catalyst used in the present invention includescompounds of first transition elements, for example, Fe, Mn, Co and Cu.One example of the transition metal catalyst includes as well organicacid salts, chlorides, phosphates, phosphites, hypophosphites andnitrates of transition metals and mixtures thereof. The organic acidincludes, for example, salts of aliphatic alkyl acids of C2 to C22 suchas acetic acid, propionic acid, octanoic acid, lauric acid, stearic acidand the like, salts of dibasic acids such as malonic acid, succinicacid, adipic acid, sebacic acid, hexahydrophthalic acid and the like,salts of butanetetracarboxylic acid, salts of aromatic acids such asbenzoic acid, toluic acid, o-phthalic acid, isophthalic acid,terephthalic acid, trimesic acid and the like and mixtures thereof.Among the transition metal catalysts, organic acid salts of Co arepreferred from the viewpoint of the oxygen-absorbing property, and Costearate is particularly preferred from the viewpoint of the safety andthe processability.

Oxygen-Absorbing Resin Composition:

A concentration of all transition elements in the above catalyst basedon the polyamide resin A in the oxygen-absorbing resin composition is 10to 5000 ppm, preferably 50 to 3000 ppm. In the above case, anoxygen-absorbing performance of the polyamide resin A can be enhanced ascompared with a case in which the addition amount deviates from theranges described above, and a deterioration in the resin processabilitydue to a reduction in the viscosity can be prevented.

A content of the polyamide resin A containing the transition metalcatalyst in the oxygen-absorbing resin composition is 15 to 60% byweight, preferably 17 to 60% by weight, more preferably 20 to 60% byweight and particularly preferably 25 to 50% by weight. When a contentof the polyamide resin A containing the transition metal catalyst in theoxygen-absorbing resin composition is less than 15 by weight or exceeds60% by weight, the oxygen-absorbing performance is reduced. Further, ifit exceeds 60% by weight, the polyamide resin A is deteriorated byoxidation, and the problem of a reduction in the strength is broughtabout.

A stabilizer and the like may suitably be added to the polyamide resin Ain the present invention. In particular, a phosphorus compound ispreferably used as a stabilizer, and to be specific, hypophosphites arepreferred. The phosphorus compound stabilizes the polyamide resin A andexerts an influence on the oxygen-absorbing performance, and thereforean addition amount thereof is preferably 200 ppm or less, particularlypreferably 100 ppm or less.

The oxygen-absorbing resin composition of the present invention can beused as a material for an oxygen absorbent in the form of a resincomposition. That is, the pellet-like or sheet-like oxygen-absorbingresin composition is filled into an air-permeable packaging material,and it may be used as a small bag-like oxygen absorbent. When it isturned into a pellet form, it is preferably crushed and turned into apowder form in order to maintain contact with oxygen. When it is turnedinto a sheet form, it is preferably stretched to provide a space betweensea island-like layers of the polyamide resin and the polyolefin resin.High density polyethylene is preferably used as the polyolefin resin instretching.

Production Process for Oxygen-Absorbing Resin Composition:

In producing the oxygen-absorbing resin composition of the presentinvention, the transition metal catalyst is preferably added to thepolyamide resin A and then mixed with the polyolefin resin.

In adding the transition metal catalyst to the polyamide resin, it isadded to the polyamide resin obtained by polycondensation of aromaticamine and dicarboxylic acid preferably by a method such as, forexample, 1) adding the transition metal catalyst after masking an end bycarboxylic acid, 2) masking an end by carboxylic acid after adding thetransition metal catalyst and 3) adding the transition metal catalystand carboxylic acid at the same time, and the good oxygen-absorbingperformance is obtained by any of the above methods.

A production process for an oxygen-absorbing resin composition in whicha master batch containing a polyolefin resin and a transition metalcatalyst is molten and kneaded with a polyamide resin is preferablylisted as another process for producing the oxygen-absorbing resincomposition.

The transition metal catalyst is kneaded with the polyolefin resin toproduce a master batch, and then the master batch is molten and mixedwith the polyamide resin A to prepare the oxygen-absorbing resincomposition. The transition metal catalyst is added so that aconcentration of all transition metals in the above catalyst based onthe polyolefin resin is preferably 200 to 5000 ppm, more preferably 300to 3000 ppm. In the above case, an oxygen-absorbing performance of thepolyamide resin A can be enhanced as compared with a case in which theaddition amount deviates from the ranges described above. Also, when theconcentration exceeds 5000 ppm, it is difficult in a certain case toproduce the master batch, or the master batch having an even quality cannot be produced in a certain case. If the transition metal catalyst isadded to the polyamide resin A, the resin processability is deterioratedby a reduction in a viscosity of the polyamide resin A.

A content of the polyamide resin A in the oxygen-absorbing resincomposition is preferably 15 to 60% by weight, more preferably 17 to 60%by weight and particularly preferably 20 to 50% by weight. If a contentof the polyamide resin A in the oxygen-absorbing resin composition fallsin the ranges described above, the oxygen-absorbing ability is enhanced.Further, the resin is inhibited from being deteriorated by oxidation ofthe polyamide resin A, and the problems of a reduction in the strengthand the like are not brought about.

The master batch used in the present invention may be used and moltenand kneaded with the polyolefin resin together with the polyamide resinA to control the polyamide resin A and the transition metal catalyst tothe desired contents.

Oxygen-Absorbing Multilayer Film:

The oxygen-absorbing resin composition of the present invention is usedpreferably as an oxygen-absorbing multilayer film comprising at least asealant layer or an oxygen permeating layer containing a polyolefinresin, an oxygen-absorbing layer containing an oxygen-absorbing resincomposition and a gas-barriering layer containing a gas-barriering filmin the form of a film or a sheet.

The present invention relates to an oxygen-absorbing multilayer filmcomprising at least three layers of a sealant layer or an oxygenpermeating layer comprising a thermoplastic resin, an oxygen-absorbingresin layer containing a polyolefin resin, a transit metal catalyst anda polyamide resin and a gas-barriering layer comprising a gas-barrieringfilm, wherein the above polyamide resin is a polyamide resin which isobtained by polycondensation of aromatic diamine and dicarboxylic acidand in which a concentration of an end amino group is 30 μeq/g or less,and a total content of the transition metal catalyst and the polyamideresin in the oxygen-absorbing resin layer is 15 to 60% by weight.

That is, the oxygen-absorbing multilayer film of the present inventionis an oxygen-absorbing multilayer film prepared by laminating at leastthree layers of a sealant layer or an oxygen permeating layer comprisinga thermoplastic resin, an oxygen-absorbing resin layer and agas-barriering layer in this order, wherein the oxygen-absorbing resincomposition of the present invention described above is contained in theoxygen-absorbing resin layer. Further, the oxygen-absorbing multilayerfilm of the present invention can be used as well for application inwhich main bodies and caps of containers and packaging materials areconstituted wholly or partially from the multilayer film with thesealant layer or the oxygen permeating layer turned to an inside. Therespective layers and the respective compositions of theoxygen-absorbing multilayer film shall be explained below in detail.

Sealant Layer or Oxygen Permeating Layer:

Polyolefin resins including various polyethylenes such as high densitypolyethylene, medium density polyethylene, low density polyethylene,linear low density polyethylene, ultra low density polyethylene,polyethylene produced by a metallocene catalyst and the like,polystyrene, polymethylpentene, polypropylenes such as propylenehomopolymers, propylene-ethylene block copolymers, propylene-ethylenerandom copolymers and the like can be used alone or in combination asthe thermoplastic resin used for the sealant layer or the oxygenpermeating layer. An ethylene-vinyl acetate copolymer, anethylene-methyl acrylate copolymer, an ethylene-ethyl acrylatecopolymer, an ethylene-acrylic acid copolymer, an ethylene-methacrylicacid copolymer, an ethylene-methyl methacrylate copolymer and athermoplastic elastomer may be added, if necessary, to the abovepolyolefin resins. Considering a processability of the multilayer film,the thermoplastic resin in which a melt flow rate (hereinafter shown asMFR) is 1 to 35 g/10 minutes at 200° C. and 2 to 45 g/10 minutes at 240°C. is preferably used. MFR referred to in the present specification is,unless otherwise described, MFR of the above resin measured at aspecific temperature on the condition of a load 2160 g by means of anequipment according to JIS K7210, and it is shown by a unit of “g/10minutes” together with a measuring temperature.

Also, color pigments such as titanium oxide and the like, additives suchas antioxidants, slipping agents, antistatic agents, stabilizers,lubricants and the like, fillers such as calcium carbonate, clay, mica,silica and the like, deodorants and the like may be added to thethermoplastic resin such as the polyolefin resin used for the sealantlayer or the oxygen permeating layer. In particular, an antioxidant ispreferably added in order to recycle scraps generated during theproduction and reprocess them.

A thickness of the sealant layer or the oxygen-permeating layer ispreferably smaller since the above layer is an isolation layer for theoxygen-absorbing resin layer, and it is preferably 2 to 50 μm,particularly preferably 5 to 30 μm. In the above case, a rate at whichthe oxygen-absorbing resin composition absorbs oxygen can be enhancedmore as compared with a case in which the thickness deviates from theranges described above, and the processability can be prevented frombeing damaged.

Oxygen-Absorbing Resin Layer:

In the present invention, the oxygen-absorbing resin layer comprises theoxygen-absorbing resin composition described above, and the polyolefinresin, the polyamide resin A, the transition metal catalyst and the likehave been described in the explanations of the oxygen-absorbing resincomposition. Considering a processability of the resin and an adhesiveproperty thereof with the oxygen-permeating layer, the same resin as thepolyolefin resin in the sealant layer or the oxygen-permeating layer ispreferably used for the polyolefin resin in the oxygen-absorbing resinlayer. From the viewpoint of the oxygen-absorbing performance, theoxygen permeability coefficient is preferably 80 to 200cc·mm/(m²·day·atm) (23° C., 60% RH), and if the polyolefin resin havingan oxygen permeability coefficient falling in the above range is used,the good oxygen-absorbing performance is obtained.

A thickness of the oxygen-absorbing resin layer shall not specificallybe restricted and is preferably 5 to 200 μm, particularly preferably 10to 100 μm. In the above case, a performance in which theoxygen-absorbing resin layer absorbs oxygen can be enhanced more ascompared with a case in which the thickness deviates from the rangesdescribed above, and the processability and the economical efficiencycan be prevented from being damaged. A thickness of theoxygen-permeating layer is preferably smaller since the above layer isan isolation layer for the oxygen-absorbing resin layer, and it ispreferably 5 to 200 μm, particularly preferably 10 to 80 μm. In theabove case, a rate at which the oxygen-absorbing resin layer absorbsoxygen can be enhanced more as compared with a case in which thethickness deviates from the ranges described above, and theprocessability can be prevented from being damaged.

Considering a processability of the deoxidizing multilayer film, athickness ratio of the sealant layer or the oxygen-permeating layer tothe oxygen-absorbing resin layer is preferably 1:0.5 to 1:3,particularly preferably 1:1.5 to 1:2.5. Further, considering theprocessability, an intermediate layer comprising a polyolefin resin ispresent preferably between the gas-barriering layer and theoxygen-absorbing resin layer. A thickness of the above intermediatelayer is preferably almost the same as that of the oxygen permeatinglayer in terms of the processability. In the above case, consideringdata spread attributable to processing, the thickness ratios fallingwithin ±10% shall be regarded as the same.

The oxygen-absorbing resin layer in the oxygen-absorbing multilayer filmof the present invention contains preferably at least a polyolefinresin, a modified polyethylene resin, a transition metal catalyst and apolyamide resin, and a content of the modified polyethylene resin in theabove oxygen-absorbing resin layer is 2 to 30% by weight.

The modified polyethylene resin described above which is used in thepresent invention means a polyethylene resin in which at least a part ofthe polyethylene resin is graft-modified by unsaturated carboxylic acidor an acid anhydride thereof. Polyethylene resins modified byunsaturated carboxylic acids such as acrylic acid, maleic acid,methacrylic acid, maleic anhydride, fumaric acid, itaconic acid and thelike can be shown as the examples of the modified polyethylene resin.Considering a mixing property with the polyamide resin A, an adhesiveproperty with an adjacent layer and a mixing property with thepolyolefin resin, a maleic anhydride-modified polyethylene resin isparticularly preferred.

If the modified polyethylene resin is added to the oxygen-absorbingresin layer, an adhesive property (interlayer strength) with a layeradjacent to the oxygen-absorbing resin layer is enhanced in preparingthe oxygen-absorbing multilayer film, and as a result thereof, a sealingstrength in processing it into a bag and the like is enhanced as well. Acontent of the modified polyethylene resin in the oxygen-absorbing resinlayer is preferably 2 to 30% by weight, particularly preferably 5 to 20%by weight. If a content of the modified polyethylene resin is 2% byweight or more, an effect of enhancing the interlayer strength isexcellent. If it is 30% by weight or less, the oxygen-absorbingperformance is excellent, and an adverse effect is not exerted on anodor of the film and recycling of the scraps. Considering aprocessability of the film, the modified polyethylene resin having MFRof 3 to 25 g/10 minutes at 200° C. and 4 to 35 g/10 minutes at 240° C.is preferably used.

Intermediate Layer:

Considering a processability, the oxygen-absorbing multilayer film ofthe present invention is prepared preferably by laminating at least fourlayers of a sealant layer comprising a polyolefin resin, the foregoingoxygen-absorbing resin layer containing at least a polyolefin resin, atransition metal catalyst and a polyamide resin, an intermediate layercomprising a polyolefin resin and a gas-barriering layer comprising agas-barriering film in this order. A laminate strength of the multilayerfilm is enhanced by providing the intermediate layer between theoxygen-absorbing resin layer and the gas-barriering layer.

Considering a compatibility, the same resin as the polyolefin resin usedfor the oxygen-absorbing resin layer is preferably used, as is the casewith the sealant layer, for the intermediate layer containing apolyolefin resin between the gas-barriering layer containing agas-barriering film and the oxygen-absorbing resin layer in the presentinvention. The above intermediate layer can prevent a reduction in aninterlayer strength with the gas-barriering layer which is brought aboutattributable to the transition metal catalyst released from theoxygen-absorbing resin layer. A thickness of the above intermediatelayer is preferably almost the same as a thickness of the sealant layerfrom the viewpoint of the processability, and it is preferably 2 to 50μm, particularly preferably 5 to 30 μm. In the above case, consideringdata spread attributable to processing, a thickness ratio falling within±10% shall be regarded as the same.

In processing into a film and a sheet, a thickness ratio of the sealantlayer, the oxygen-absorbing resin layer and the intermediate layer is,considering the processability, preferably 1:0.5:1 to 1:3:1,particularly preferably 1:1:1 to 1:2.5:1.

Gas-Barriering Layer:

Various deposited films of gas-barriering thermoplastic resins,gas-barriering thermosetting resins, silica, alumina, aluminum and thelike and metal foils such as aluminum foil and the like can be used as agas-barriering film used for the gas-barriering layer of the presentinvention. Ethylene-vinyl alcohol copolymer, MXD6, polyvinylidenechloride, amine-epoxy hardeners and the like can be shown as theexamples of the gas-barriering thermoplastic resins. Also,gas-barriering epoxy resins, for example, “MAXIVE” manufactured byMitsubishi Gas Chemical Co., Inc. can be shown as the examples of thegas-barriering thermosetting resins.

The present invention relates to an oxygen-absorbing multilayer filmprepared by laminating at least the sealant layer described above, theoxygen-absorbing resin layer described above, an epoxy resin-cured filmlayer and an outer layer in this order, wherein the above epoxyresin-cured film layer comprises an epoxy resin-cured film which isobtained by curing an epoxy resin composition comprising an epoxy resinand an epoxy resin curing agent as principal components and whichcontains 40% by weight or more of a skeletal structure represented bythe following Formula (1):

In the oxygen-absorbing multilayer film of the present invention, theepoxy resin-cured film layer comprises the epoxy resin-cured filmobtained by curing the epoxy resin composition comprising the epoxyresin and the epoxy resin curing agent as the principal components, andthe skeletal structure represented by Formula (1) described above iscontained in the above epoxy resin-cured film in a proportion of 40% byweight or more, preferably 45% by weight or more, more preferably 50% byweight or more. The skeletal structure represented by Formula (1) iscontained in the above epoxy resin-cured film in a high level, wherebythe high gas-barriering property is exerted. According to the presentinvention, the epoxy resin-cured film having an oxygen-barrieringproperty of an oxygen permeability coefficient of 1.0 mL·mm/(m²·day·MPa)(23° C., 60% RH) or less can be obtained as well. The epoxy resin andthe epoxy resin curing agent which are the principal components of theepoxy resin composition shall be explained below.

The epoxy resin in the present invention may be any of aliphaticcompounds, alicyclic compounds, aromatic compounds and heterocycliccompounds. Considering to exert the high gas-barriering property, epoxyresins containing aromatic parts in a molecule are preferred, and epoxyresins containing the skeletal structure represented by Formula (1)described above in a molecule are more preferred. The specific examplesthereof include epoxy resins having a glycidylamino group derived frommetaxylylenediamine, epoxy resins having a glycidylamino group derivedfrom 1,3-bis(aminomethyl)cyclohexane, epoxy resins having aglycidylamino group derived from diaminodipheylmethane, epoxy resinshaving a glycidylamino group and/or a glycidyloxy group derived fromparaminophenol, epoxy resins having a glycidyloxy group derived frombisphenol A, epoxy resins having a glycidyloxy group derived frombisphenol F, epoxy resins having a glycidyloxy group derived from phenolnovolac, epoxy resins having a glycidyloxy group derived from resorcinoland the like. Among them, preferred are the epoxy resins having aglycidylamino group derived from metaxylylenediamine, the epoxy resinshaving a glycidylamino group derived from1,3-bis(aminomethyl)cyclohexane, the epoxy resins having a glycidyloxygroup derived from bisphenol F and the epoxy resins having a glycidyloxygroup derived from resorcinol.

Further, the epoxy resins having a glycidyloxy group derived frombisphenol F and the epoxy resins having a glycidylamino group derivedfrom metaxylylenediamine are more preferably used as the principalcomponents, and the epoxy resins having a glycidylamino group derivedfrom metaxylylenediamine are particularly preferably used as theprincipal component.

The various epoxy resins described above can be used as well by mixingthem in a suited proportion in order to enhance various performancessuch as the flexibility, the impact resistance, the heat and moistureresistance and the like.

The epoxy resins described above are obtained by reacting alcohols,phenols or amines with epihalohydrin. For example, the epoxy resinshaving a glycidylamino group derived from metaxylylenediamine areobtained by adding metaxylylenediamine to epichlorohydrin.Metaxylylenediamine has four amino hydrogens, and therefore the mono-,di-, tri- and tetraglycidyl compounds are formed. The number of theglycidyl group can be changed by changing a reaction ratio ofepichlorohydrin to metaxylylenediamine. For example, mainly an epoxyresin having 4 glycidyl groups is obtained by subjectingmetaxylylenediamine to addition reaction with about 4 times mole ofepichlorohydrin.

The epoxy resins described above are synthesized by reacting variousalcohols, phenols and amines with excess epihalohydrin under thepresence of alkali such as sodium hydroxide and the like on atemperature condition of 20 to 140° C., preferably 50 to 120° C. in acase of the alcohols and the phenols and 20 to 70° C. in a case of theamines and separating alkali halides produced.

A number average molecular weight of the epoxy resin produced is variedaccording to a mole ratio of epihalohydrin to various alcohols, phenolsand amines, and it is about 80 to 4000, preferably about 200 to 1000 andmore preferably about 200 to 500.

The epoxy resin curing agent in the present invention may be any ofaliphatic compounds, alicyclic compounds, aromatic compounds andheterocyclic compounds, and epoxy resin curing agents which can usuallybe used such as polyamines, phenols, acid anhydrides or carboxylic acidscan be used. The above epoxy resin curing agents can be selectedaccording to use applications of the laminate film and the requiredperformances in applications thereof.

To be specific, the polyamines include aliphatic amines such asethylenediamine, diethylenetriamine, triethylenetetraamine,tetraethylenepentaamine and the like; aliphatic amines having aromaticrings such as metaxylylenediamine, paraxylylenediamine and the like;alicyclic amines such as 1,3-bis(aminomethyl)cyclohexane,isophoronediamine, norbornanediamine and the like; and aromatic aminessuch as diaminodiphenylmethane, metaphenylenediamine and the like.Further, capable of being also used as the epoxy resin curing agent areepoxy resins prepared by using the above compounds as raw materials,modifying reaction products of polyamines with monoglycidyl compounds,modifying reaction products of polyamines with epichlorohydrin,modifying reaction products of polyamines with alkylene oxides having 2to 4 carbon atoms, amidooligomers obtained by reacting polyamines withmultifunctional compounds having at least one acyl group andamidooligomers obtained by reacting polyamines with multifunctionalcompounds having at least one acyl group and monovalent carboxylic acidsand/or derivatives thereof.

The phenols include polyhydric phenols such as catechol, resorcinol,hydroquinone and the like and resole type phenol resins.

Also, capable of being used as the acid anhydrides or the carboxylicacids are aliphatic acid anhydrides such as dodecenylsuccinic anhydride,polyadipic anhydride and the like, alicyclic acid anhydrides such as(methyl)tetrahydrophthalic anhydride, (methyl)hexahydrophthalicanhydride and the like, aromatic acid anhydrides such as phthalicanhydride, trimellitic anhydride, pyromellitic anhydride and the likeand carboxylic acids thereof.

Considering to exert the high gas-barriering property, the epoxy resincuring agents containing aromatic parts in a molecule are preferred, andthe epoxy resin curing agents containing the skeletal structurerepresented by Formula (1) in a molecule are more preferred.

To be specific, more preferably used are reaction products ofmetaxylylenediamine or paraxylylenediamine with epoxy resins obtained byusing the above compounds as raw materials or monoglycidyl compounds,reaction products thereof with alkylene oxides having 2 to 4 carbonatoms, reaction products thereof with epichlorohydrin, reaction productsthereof with multifunctional compounds having at least one acyl groupwhich can form an amide group part by reaction with the above polyaminesto form oligomers and reaction products of multifunctional compoundshaving at least one acyl group which can form an amide group part byreaction with the above polyamines to form oligomers with monovalentcarboxylic acids and/or derivatives thereof.

Considering the high gas-barriering property and the good adhesiveproperty, reaction products of (A) and (B) shown below or reactionproducts of (A), (B) and (C) shown below are particularly preferablyused as the epoxy resin curing agents:

(A) metaxylylenediamine or paraxylylenediamine,(B) multifunctional compounds having at least one acyl group which canform an amide group part by reaction with polyamines to form oligomersand(C) monovalent carboxylic acids having 1 to 8 carbon atoms and/orderivatives thereof.

The multifunctional compounds (B) having at least one acyl group whichcan form an amide group part by reaction with polyamines to formoligomers include carboxylic acids such as acrylic acid, methacrylicacid, maleic acid, fumaric acid, succinic acid, malic acid, tartaricacid, adipic acid, isophthalic acid, terephthalic acid, pyromelliticacid, trimellitic acid and the like and derivatives thereof, forexamples, esters, amides, acid anhydrides, acid chlorides and the like,and acrylic acid, methacrylic acid and derivatives thereof areparticularly preferred.

Further, monovalent carboxylic acids having 1 to 8 carbon atoms such asformic acid, acetic acid, propionic acid, butyric acid, lactic acid,glycolic acid, benzoic acid and the like and derivatives thereof, forexamples, esters, amides, acid anhydrides, acid chlorides and the likemay be used in combination with the multifunctional compounds describedabove and reacted with initiating polyamines. The amide group partsderived by the reaction have a high cohesive force, and the amide groupparts present in the epoxy resin curing agent in a high proportionprovide the higher gas-barriering property and the good adhesivestrength.

A reaction mole ratio of (A) and (B) or (A), (B) and (C) described abovefalls preferably in a range of 0.3 to 0.97 in terms of a ratio of thenumber of reactive functional groups contained in (B) to the number ofamino groups contained in (A) or a ratio of the number of reactivefunctional groups contained in (B) and (C) to the number of amino groupscontained in (A). If the ratio is smaller than 0.3, a sufficiently largeamount of the amide groups is not formed in the epoxy resin curingagent, and the gas-barriering property of a high level and the adhesiveproperty of a high level are not exerted. Further, a proportion ofvolatile molecules remaining in the epoxy resin curing agent iselevated, and it is a cause of odor generated from the cured filmobtained. Also, a proportion of hydroxyl groups formed by the reactionof the epoxy groups with the amino groups in the cured reaction productis elevated, and therefore it is a factor of a marked reduction in theoxygen-barriering property under high humidity environment. On the otherhand, if it falls in a range of higher than 0.97, an amount of the aminogroups reacting with the epoxy groups is reduced, and the excellentimpact resistance and the excellent heat resistance are not exerted.Further, the solubility in various organic solvents and water is reducedas well. Particularly considering a high gas-barriering property, a highadhesive property, inhibition of generating odor and a highoxygen-barriering property under high humidity environment in the curedfilm obtained, a mole ratio of the multifunctional compound to thepolyamine component falls more preferably in a range of 0.6 to 0.97.Considering to exert the adhesive property of a higher level, at least6% by weight of the amide group based on a whole amount of the epoxyresin curing agent is preferably contained in the above curing agent inthe present invention.

Considering to exert the adhesive property to the base material, areaction ratio in the reaction product of metaxylylenediamine orparaxylylenediamine which is the epoxy resin curing agent with themultifunctional compound having at least one acyl group which can forman amide group part by reaction with the above polyamines to form anoligomer falls in a range of 0.6 to 0.97, preferably 0.8 to 0.97 andparticularly preferably 0.85 to 0.97 in terms of a mole ratio of themultifunctional compound to the polyamine component, and the epoxy resincuring agent elevating an average molecular weight of the oligomer whichis the reaction product is preferably used.

The more preferred epoxy resin curing agent is a reaction product ofmetaxylylenediamine with acrylic acid, methacrylic acid and/orderivatives thereof. In this regard, a reaction mole ratio of acrylicacid, methacrylic acid and/or the derivatives thereof tometaxylylenediamine falls preferably in a range of 0.8 to 0.97.

In general, a blend proportion of the epoxy resin and the epoxy resincuring agent which are the principal components of the epoxy resin-curdfilm in the present invention may be a standard blend range in preparingan epoxy resin-curd film by reaction of an epoxy resin with an epoxyresin curing agent. To be specific, a ratio of the number of activehydrogens in the epoxy resin curing agent to the number of epoxy groupsin the epoxy resin falls in a range of 0.5 to 5.0. If it falls in arange of smaller than 0.5, the remaining unreacted epoxy groups are acause of reducing a gas-barriering property of the cured film obtained,and if it falls in a range of larger than 5.0, the remaining unreactedamino groups are a cause of reducing a heat and humidity resistance ofthe cured film obtained. Particularly considering a gas-barrieringproperty and a heat and humidity resistance of the cured film obtained,the ratio falls in a range of more preferably 0.8 to 3.0, particularlypreferably 0.8 to 2.0.

Also, considering to exert a high oxygen-barriering property of thecured film obtained under high humidity environment, a ratio of thenumber of active hydrogens in the epoxy resin curing agent to the numberof epoxy groups in the epoxy resin falls preferably in a range of 0.8 to1.4.

On the other hand, when carrying out thermoforming as is the case withthermoformed containers, the ratio falls in a range of preferably 1.6 to5.0, more preferably 2.0 to 4.5.

A thermosetting resin composition such as a polyurethane base resincomposition, a polyacryl base resin composition, a polyurea base resincomposition and the like may be mixed, if necessary, with the epoxyresin composition in the present invention as long as the effects of thepresent invention are not damaged.

A wetting agent such as silicone or acryl base compounds may be added,if necessary, to the epoxy resin composition in the present invention inorder to aid wetting of a surface in coating it on various materials.The suited wetting agent includes BYK331, BYK333, BYK347, BYK348,BYK354, BYK380, BYK381 and the like which are available from BYK ChemieAG. When adding them, a proportion thereof falls preferably in a rangeof 0.01 to 2.0% by weight based on a whole weight of the epoxy resincomposition.

Also, in order to enhance various performances such as a gas-barrieringproperty, an impact resistance, a heat resistance and the like of theepoxy resin-cured matter layer in the present invention, an inorganicfiller such as silica, alumina, mica, talc, aluminum flakes, glassflakes and the like may be added to the epoxy resin composition.

Considering a transparency of the film, the above inorganic filler ispreferably tabular. When adding them, a proportion thereof fallspreferably in a range of 0.01 to 10.0% by weight based on a whole weightof the epoxy resin composition.

Further, in order to enhance an adhesive property of the epoxyresin-cured matter layer to the base material, a coupling agent such asa silane coupling agent, a titan coupling agent and the like may beadded to the epoxy resin composition. Commercially available couplingagents can be used as the coupling agent, and among them, preferred arecompounds having organic functional groups which can react with thegas-barriering resin composition of the present invention includingamino base silane coupling agents such asN-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane,N-(2-aminoethyl)-3-aminopropylmethyltrimethoxysilane,3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane,N,N′-bis[[3-trimethoxysilyl]propyl]ethylenediamine and the like, epoxybase silane coupling agents such as 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropylmethyldimethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,3-glycidoxypropyltriethoxysilane and the like, methacryloxy base silanecoupling agents such as 3-methacryloxypropyl-trimethoxysilane and thelike, mercapto base silane coupling agents such as3-mercaptopropyltrimethoxysilane and the like, isocyanate base silanecoupling agents such as 3-isocyanatepropyltriethoxysilane and the likewhich are available from Chisso Corporation, Dow Corning Toray Co.,Ltd., Shin-Etsu Chemical Co., Ltd. and the like. When adding the abovecompounds, a proportion thereof falls preferably in a range of 0.01 to5.0% by weight based on a whole weight of the epoxy resin composition.When the base material is a film on which various inorganic compoundssuch as silica, alumina and the like are deposited, the silane couplingagent is more preferred.

The outer layer in the present invention includes, for example,polyester base films of polyethylene terephthalate, polybutyleneterephthalate and the like; polyamide base films of nylon 6, nylon 6,6,metaxyleneadipamide (N-MXD6) and the like; polyolefin base films of lowdensity polyethylene, high density polyethylene, linear low densitypolyethylene, polypropylene and the like; polyacrylonitrile base films;poly(meth)acryl base films; polystyrene base films; polycarbonate basefilms; ethylene-vinyl alcohol copolymer (EVOH) base films; polyvinylalcohol base films; papers such as carton and the like; and metal foilsof aluminum, copper and the like. Also, capable of being used are filmsobtained by coating various polymers such as polyvinylidene chloride(PVDC) resins, polyvinyl alcohol resins, ethylene-vinyl acetatecopolymer-saponified base resins, acryl base resins and the like onvarious materials used as the above base materials; films on whichvarious inorganic compounds or metals such as silica, alumina, aluminumand the like are deposited; films in which inorganic fillers and thelike are dispersed; and films provided with an oxygen-scavengingfunction.

The epoxy resin-cured film in the present invention is characterized byhaving a high gas-barriering property in addition to an adhesiveperformance to the suited base materials, and it shows a highgas-barriering property in a wide range extending from a low humiditycondition to a high humidity condition. This allows gas-barriering filmsprepared by using the epoxy resin-cured film in the present invention toexert a gas-barriering property of a very high level without usinggas-barriering materials usually used such as inorganic film-depositedfilms on which deposited are a PVCD coating layer, a polyvinyl alcohol(PVA) coating layer, an ethylene-vinyl alcohol copolymer (EVOH) filmlayer, a metaxylyleneadipamide film layer, alumina, silica and the like.When an inorganic film-deposited film is used as an outer layer, use ofthe epoxy resin-cured film makes it possible to notably reduce a degreeof deterioration of a gas-barriering property caused by sudden bending.

Gas-barriering films such as ethylene-vinyl alcohol copolymer (EVOH)base films, polyvinyl alcohol base films, polyvinyl alcohol coatingfilms, polyvinyl alcohol coating films in which inorganic fillers aredispersed, metaxylyleneadipamide (N-MXD6) films and the like have thedefect that a gas-barriering property thereof is reduced under a highhumidity condition, but the above defect can be solved by using theepoxy resin-cured film in the present invention to prepare the filmusing the above gas-barriering films for an outer layer.

Further, the epoxy resin-cured film in the present invention isexcellent in a toughness and a heat and humidity resistance, andtherefore gas-barriering films excellent in an impact resistance, aboiling treatment resistance, a retort treatment resistance and the likeare obtained.

In order to inhibit foaming of a coating liquid of the epoxy resincomposition in the present invention in preparing the coating liquid, adefoaming agent such as silicone, acryl base compounds and the like maybe added to the coating liquid. The suited defoaming agent includesBYK019, BYK052, BYK065, BYK066N, BYK067N, BYK070, BYK080 and the likewhich are available from BYK Chemie AG., and BYK065 is particularlypreferred. When the above defoaming agents are added, a proportionthereof falls in a range of preferably 0.01 to 3.0% by weight, morepreferably 0.02 to 2.0% by weight based on a whole weight of the epoxyresin composition.

A thickness of the gas-barriering layer in using the thermoplastic resinas the gas-barriering resin in the present invention for thegas-barriering layer is preferably 5 to 200 μm, particularly preferably10 to 100 μm. Also, when a thermosetting resin such as the epoxyresin-cured film described above is used for the gas-barriering adhesivelayer, a thickness thereof is preferably 0.1 to 100 μm, more preferably0.1 to 30 μm, further preferably 0.2 to 20 μm and particularlypreferably 0.2 to 10 μm. When the thickness falls in the rangesdescribed above, the gas-barriering property and the adhesive propertycan be enhanced more as compared with a case in which the thicknessdeviates from the ranges described above, and the processability and theeconomical efficiency such as the drying property and formation of thegas-barriering layer having an even thickness can be prevented frombeing damaged.

Other Layer:

In the present invention, a protective layer comprising a thermoplasticresin is preferably provided on an inside or an outside of thegas-barriering layer in order to prevent breakage and pin holes of thegas-barriering layer. The resin used for the protective layer includesthe resins constituting the outer layer of the epoxy resin-cured filmdescribed above, and in addition thereto, it includes, for example,polyethylenes such as high density polyethylene and the like,polypropylenes such as propylene homopolymers, propylene-ethylene randomcopolymers, propylene-ethylene block copolymers and the like, polyamidessuch as nylon 6, nylon 6,6 and the like, polyesters such as PET and thelike and combinations thereof.

Oxygen-Absorbing Multilayer Film:

The oxygen-absorbing multilayer film of the present invention comprisesat least three layers of the sealant layer or the oxygen permeatinglayer, the oxygen-absorbing resin layer and the gas-barriering layereach described above and has preferably an intermediate layer betweenthe oxygen-absorbing resin layer and the gas-barriering layer, and ithas, if necessary, the other layer described above. A production methodfor the oxygen-absorbing multilayer film can make use of publicly knownmethods such as a coextrusion method, various laminating methods,various coating methods and the like according to the properties of thevarious materials, the processing purpose, the processing steps and thelike. For example, molding of the film and the sheet includes a methodin which they are produced by extruding the molten resin compositionfrom an adjunct extruding equipment through a T die, a circular die andthe like and a method in which they are produced by coating an adhesiveon an oxygen-absorbing film or sheet and sticking it on other films orsheets. Also, a multilayer container having a prescribed form can bemolded at one blow by co-injecting or successively injecting the moltenresin composition into an injection metal die through a multilayermultiple dice by means of an injection equipment.

Oxygen-Absorbing Multilayer Container:

The oxygen-absorbing multilayer container of the present invention isprepared by thermoforming the oxygen-absorbing multilayer film describedabove.

The oxygen-absorbing multilayer film obtained can be prepared in theform of a film and used by processing into a bag and a cover material.Also, it can be prepared in the form of a sheet and thermoformed intothe oxygen-absorbing multilayer container having a prescribed form suchas trays, cups, bottles, tubes, PTP (press•through•pack) and the like bya molding method such as vacuum molding, compression molding, plugassist molding and the like. Further, the oxygen-absorbing multilayercontainer can be subjected to boiling treatment at 80 to 100° C. andsemi-retort, retort and high retort treatments at 100 to 135° C. Also,it can be used preferably for a pouch provided with aneasy-vapor-passing port which meets cooking by an electronic oven,wherein the bag-like container provided with an opened port is filledwith a content such as food and the like, and vapor is released from theabove opened port in heating and cooking the content by the electronicoven.

The oxygen-absorbing multilayer film and the oxygen-absorbing multilayercontainer of the present invention are used for a part or a whole partof a packaging container for tight sealing with the sealant layer or theoxygen permeating layer turned•to an inside, whereby oxygen in thecontainer as well as a small amount of oxygen coming in from an outsideof the container can be absorbed to prevent a content in the containerfrom changing in quality due to oxygen.

The oxygen-absorbing multilayer film described above can be used as anoxygen-absorbing paper container by laminating a paper substrate on theouter layer of the gas-barriering layer.

The present invention relates to the oxygen-absorbing multilayercontainer prepared by subjecting a laminated material prepared bylaminating at least a paper substrate, a gas-barriering layer, theoxygen-absorbing resin layer of the present invention and athermoplastic resin inner layer in this order to containermanufacturing.

A thermoplastic resin outer layer may be provided, if necessary, on anouter layer of the paper substrate. It can be thermally fused with thethermoplastic resin inner layer described above to tightly seal thecontainer.

In respect to a processability of the paper container prepared bylaminating the paper substrate, a thickness of an inside part of thegas-barriering layer is preferably 60 μm or less, particularlypreferably 50 μm or less. If a thickness of the inside part is largerthan that of the gas-barriering layer, a problem is brought about on aprocessability into the container in laminating the paper substrate andmolding it into a container form.

The paper substrate is a substrate constituting the paper container andprovides it with a formability, a flexibility, a rigidity, a toughness,a strength and the like, and for example, strong sizing, bleached ornon-bleached paper substrates, white roll papers, craft papers, boardpapers, processed papers and the like can be used therefor. Papershaving a basis weight of 80 to 600 g/m², preferably papers having abasis weight of 100 to 450 g/m² are preferred as the paper substrate.The paper substrate may be provided with printings such as characters,figures, marks, pictures, patterns and the like.

The oxygen-absorbing paper container can be various paper containers ofa gable top type, a brick type, a flat top type and the like.

The oxygen-absorbing paper container can suitably be used, for example,for milk, milk products, juice, coffee, alcoholic beverages, carbonatedbeverages, liquid seasonings such as soy sauce, noodle soup, stock andthe like, chemicals, drugs, detergents and the like.

The present invention relates to an oxygen-absorbing sealed containerwhich comprises a cover material comprising the oxygen-absorbingmultilayer film of the present invention and a gas-barriering moldedcontainer prepared by laminating at least three layers of athermoplastic resin inner layer, a gas-barriering layer and athermoplastic resin outer layer in this order and which is prepared bybonding the above sealant layer to the thermoplastic resin inner layerby heat sealing.

The oxygen-absorbing multilayer film constituting the cover material inthe oxygen-absorbing sealed container of the present invention is theoxygen-absorbing multilayer film of the present invention and isprepared by laminating at least three layers of a sealant layer or anoxygen permeating layer, an oxygen-absorbing resin layer and agas-barriering layer in this order, and the oxygen-absorbing resin layercontains a polyamide resin A which is obtained by polycondensation ofaromatic diamine and dicarboxylic acid and in which an end amino groupconcentration is 30 μeq/g or less, a transition metal catalyst and apolyolefin resin.

The gas-barriering molded container constituting the oxygen-absorbingsealed container of the present invention is a gas-barriering moldedcontainer prepared by laminating at least three layers of athermoplastic resin outer layer, a gas-barriering layer and athermoplastic resin inner layer from an outside of the container.

A thermoplastic resin is used for the thermoplastic resin outer layerand the thermoplastic resin inner layer constituting the gas-barrieringmolded container. Various polyethylenes such as high densitypolyethylene, medium density polyethylene, low density polyethylene,linear low density polyethylene, ultra low density polyethylene,polyethylene produced by a metallocene catalyst and the like,polystyrene, ethylene-vinyl acetate copolymers, ionomers,ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers,ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers,ethylene-methyl methacrylate copolymers, polymethylpentene, variouspolypropylenes such as propylene homopolymers, propylene-ethylene blockcopolymers, propylene-ethylene random copolymers, polypropylene producedby a metallocene catalyst and the like, thermoplastic elastomers,polyethylene terephthalate, nylons and the like can be used alone or incombination for the thermoplastic resin used.

A gas-barriering film is used for the gas-barriering layer constitutingthe gas-barriering molded container. An ethylene-vinyl alcoholcopolymer, nylon MXD6, polyvinylidene chloride and aluminum are shown asthe examples of the gas-barriering film. When carrying out heatingtreatment of 80° C. or higher such as retort, boiling sterilization andthe like, nylon MXD6 is particularly preferably used. A nylon MXD6 resincomposition prepared by mixing nylon MXD6 with non-crystalline nylon maybe used.

The oxygen-absorbing sealed container of the present invention comprisesthe cover material comprising the oxygen-absorbing multilayer film andthe gas-barriering molded container each described above and is obtainedby bonding the sealant layer of the above cover material to thethermoplastic resin inner layer of the above molded container by heatsealing, and it provides the effect that iron powder is not adhered on aflange part.

The oxygen-absorbing multilayer container of the present invention canabsorb oxygen regardless of the presence of moisture in the stored filmand therefore can suitably be used for dried foods such as powderseasonings, powder coffee, coffee beans, rice, tea, beans, baked ricecrackers, rice crackers and the like, drugs, health foods such asvitamin preparations and the like. In addition thereto, theoxygen-absorbing multilayer container obtained in the present inventioncan suitably be used, unlike conventional oxygen-absorbing resincompositions in which iron powder is used, for alcohol beverages andcarbonated beverages, acetic acid-containing foods and the like whichcan not be stored due to the presence of iron and applications in whichhydrogen peroxide sterilization is carried out for sterilizingcontainers.

In addition thereto, capable of being listed as the stored goods areprocessed rices such as milled rice, cooked rice, festive red rice, ricecakes and the like, cooked foods such as soup, stew, curry and the like,fruits, sweet stuffs such as sweet jelly of beans, purine, cakes,steamed bean-lam bun and the like, fishery products such as tuna,fishes, shellfishes and the like, milk processed products such ascheese, butter and the like, meat, meat processed products such assalami, sausage, ham and the like, vegetables such as carrot, potato,asparagus, shiitake mushroom and the like and eggs.

Method for Storing a Content of a Fluid Infusion Container:

The present invention relates to a method for preserving a content of afluid infusion container in which a content of a fluid infusioncontainer is preserved in an oxygen-absorbing container prepared byusing wholly or partially an oxygen-absorbing multilayer film preparedby laminating at least three layers of an oxygen-permeating layercomprising a thermoplastic resin, an oxygen-absorbing resin layercontaining at least a polyolefin resin, a transition metal catalyst anda polyamide resin and a gas-barriering layer comprising a gas-barrieringfilm in order from an inside, wherein the above polyamide resin is apolyamide resin which is obtained by polycondensation of at leastaromatic diamine and dicarboxylic acid and in which an end amino groupconcentration is 30 μeq/g or less, and a total content of the transitionmetal catalyst and the polyamide resin in the oxygen-absorbing resinlayer is 15 to 60% by weight.

The fluid infusion container is constituted from, for example,polyolefins such as polyethylene, polypropylene and the like from theviewpoint of a moisture resistance, a sanitary property and the like.The above resins are excellent in a moisture resistance and a sanitaryproperty but inferior in a gas-barriering property. The oxygen-absorbingmultilayer container of the present invention is excellent in agas-barriering property and can effectively reduce oxygen remaining inthe oxygen-absorbing multilayer film, and therefore even if the fluidinfusion container is filled with a content liquid which is likely to bechanged in quality by oxygen, the content liquid can be preservedtherein without changing in quality.

Shown as the examples of the content liquid which is likely to bechanged in quality by oxygen are transfusion materials containing aminoacid components such as L-isoleucine, L-leucine, L-lysine, L-methionine,L-phenylalanine, L-threonine, L-valine, L-tyrosine, L-tryptophan,L-arginine, L-histidine, L-alanine, L-asparagine, aminoacetic acid,L-proline, L-serine and the like and in addition thereto, transfusionmaterials containing sugar contents, fats and vitamins as well ascardiovascular agents such as dobutamine hydrochloride, dopaminehydrochloride and the like and preparations containing them.

The content of the fluid infusion container is tightly sealed in anoxygen-absorbing container prepared by using wholly or partially anoxygen-absorbing multilayer film prepared by laminating at least threelayers of an oxygen-permeating layer comprising a thermoplastic resin,an oxygen-absorbing resin layer containing a polyamide resin A, atransition metal catalyst and a polyolefin resin and a gas-barrieringlayer comprising a gas-barriering film in order from an inside, and itis stored. This makes it possible to absorb oxygen in the container aswell as a small amount of oxygen coming in from an outside of thecontainer to prevent the content in the fluid infusion container fromchanging in quality due to oxygen. Further, use of the member having atransparency makes it possible to confirm a content without opening thepackaging container, and therefore the packaging container having a goodhandling property is obtained. Further, the oxygen-absorbing containerprepared by using wholly or partially the oxygen-absorbing multilayerfilm of the present invention can be used as well for the fluid infusioncontainer to preserve a content of the fluid infusion container.

EXAMPLES

The present invention shall be explained below in further details withreference to examples and comparative examples, but the presentinvention shall not be restricted by them. In the following examples andcomparative examples, various physical property values were measured bythe following measuring methods and measuring equipments.

Measuring Method of Tg:

Tg was measured according to JIS K7122. “DSC-60” manufactured byShimadzu Corporation was used for a measuring equipment.

Measuring Method of Melting Point:

A DSC melting peak temperature was measured for the melting pointaccording to ISO 11357. “DSC-60” manufactured by Shimadzu Corporationwas used for a measuring equipment.

Measuring Method of Number Average Molecular Weight:

The number average molecular weight was measured by GPC-LALLS. “ShodexGPC-2001” manufactured by Showa Denko K.K. was used for a measuringequipment.

Measuring Method of MFR:

MFR of the respective resins was measured at a specific temperature onthe condition of a load 2160 g by means of an equipment according to JISK7120 (“Melt Indexer” manufactured by Toyo Seiki Seisaku-sho, Ltd.), anda value thereof was shown together with the temperature (unit: “g/10minutes”). When MFR was measured according to JIS K7120, it wasspecifically described accordingly.

Measuring Method of Oxygen Permeability Coefficient:

The oxygen permeability coefficient was measured on the conditions of23° C.·60% RH and a cell area of 50 cm² by means of “OX-TRAN-2/21”manufactured by MOCON, Inc.

Measuring Method of End Amino Group Concentration:

The sample 0.5 g was dissolved in 30 mL of phenol/ethanol=4/1 (volumeratio), and 5 mL of methanol was added thereto. Hydrochloric acid of0.01 normal was used as a titrating liquid to titrate the solution bymeans of an automatic titrating equipment (“COM-2000” manufactured byHiranuma Seisakusho Co., Ltd.). The same operation carried out withoutadding the sample was set to a blank, and the end amino groupconcentration was calculated from an equation shown below:

end amino group concentration (μeq/g)=(A−B)×f×10/C

-   -   (A: titration amount (mL), B: blank titration amount (mL), f:        factor of the titrating liquid, C: sample amount (g)).

Measuring Method of End Carboxyl Group Concentration:

The sample 0.5 g was dissolved in 30 mL of benzyl alcohol, and 10 mL ofmethanol was added thereto. A sodium hydroxide solution of 0.01 normalwas used as a titrating liquid to titrate the solution by means of theautomatic titrating equipment (“COM-2000” manufactured by HiranumaSeisakusho Co., Ltd.). The same operation carried out without adding thesample was set to a blank, and the end carboxyl group concentration wascalculated from an equation shown below:

end carboxyl group concentration (μeq/g)=(A−B)×f×10/C

-   -   (A: titration amount (mL), B: blank titration amount (mL), f:        factor of the titrating liquid, C: sample amount (g)).

Measuring Method of Semi-Crystallization Time:

When the pellets are molten at the respective temperatures tocrystallize the resin at the respective temperatures, time required forcrystallization of a whole part is called crystallization time, and timerequired for 50% of crystallization is called semi-crystallization time.The semi-crystallization time was measured by a depolarized lightintensity method. That is, the molten sample pellet was irradiated withlight, and a permeation amount of light was decreased as the samplepellet was crystallized; a point in which it was stabilized was set tocrystallization, and time required for it was set to crystallizationtime; and time at which a permeation amount of light reached 50% ofcrystallization was set to semi-crystallization time. Thecrystallization time and the semi-crystallization time were variedaccording to the measuring temperatures, and in the followingdescriptions, the shortest semi-crystallization time out of thesemi-crystallization times at the respective temperatures was describedas the “semi-crystallization time”. The crystallization time and thesemi-crystallization time were measured by means of a “polymercrystallization rate measuring equipment model MK-701” manufactured byKotaki Co., Ltd.

Synthetic Conditions of Polyamide Resin in Melt Polymerization:

After dicarboxylic acid was heated at 170° C. and molten in a reactioncontainer, aromatic diamine was gradually and continuously dropwiseadded thereto while stirring the content so that a mole ratio thereof tothe dicarboxylic acid was about 1:1, and the temperature was elevated upto 240° C. After finishing dropwise adding, the temperature was elevatedup to 260° C. to continue the reaction. After finishing the reaction,the reaction container was slightly pressurized by nitrogen, and thestrand was extruded from the die head having a hole and pelletized bymeans of a pelletizer.

Synthetic Conditions of Polyamide Resin in Solid Phase Polymerization:

A rotary tumbler equipped with a heating device was charged with thepellets obtained by carrying out the melt polymerization by the methoddescribed above, and operation in which the tumbler was reduced inpressure down to 1 torr while rotating the tumbler and then returned toatmospheric pressure by nitrogen was carried out three times. Then, theequipment was heated while maintaining an inside of the equipment at 30torr by rotating the tumbler to control an inside of the equipment to150° C., and the reaction was continued at the temperature forprescribed time. Then, the equipment was cooled down to 60° C. to obtaina polyamide resin.

Measuring Method of Sealing Strength:

Measured according to JIS Z1526 by means of a tensile test equipment.

Measuring Method of Heat Fusion Strength:

Measured according to JIS Z1526 by means of a tensile test equipment.

Oxygen-Absorbing Resin Composition Example 1A

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1A). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 1A had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 17.5 μeq/g, an end carboxylgroup concentration of 91.6 μeq/g, a number average molecular weight of23500 and MFR of 11.0 g/10 minutes at 240° C. A non-stretched film wasprepared from the resulting polyamide 1A alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1A through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1A) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Kernel KF380” manufactured by Japan PolyethyleneCorporation, MFR: 4.0 g/10 minutes (measured according to JIS K7210),MFR: 8.7 g/10 minutes at 240° C., MFR: 10.0 g/10 minutes at 250° C.,hereinafter referred to as LLDPE) in a weight ratio of the cobaltstearate-containing polyamide 1A:LLDPE=35:65 to obtain anoxygen-absorbing resin composition. Then, the above oxygen-absorbingresin composition was used to obtain a film having a thickness of 50 μmand comprising a single layer of the oxygen-absorbing resin composition,and an appearance of the film was observed to find that an appearance ofthe film was good. The above film was cut into two films of 10×10 mm,and each two sheets of the above film were put in gas-barriering bagswhich comprised an aluminum foil-laminated layer film and in whichmoisture contents in the bags were 30% and 100% together with 300 ml ofair, followed by tightly sealing the bags. They were stored at 23° C. tomeasure a whole amount of oxygen absorbed for 7 days after tightlysealed. On the other hand, an elongation rate of the film after storedat 40° C. and a humidity of 100% for one month was measured. The resultsthereof are shown in Table 2A.

Example 2A

A film was produced in the same manner as in Example 1A to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1A:LLDPE=55:45. The results thereof are shown in Table 2A.

Example 3A

A film was produced in the same manner as in Example 1A to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1A:LLDPE=25:75. The results thereof are shown in Table 2A.

Example 4A

Metaxylylenediamine and adipic acid were used in a mole ratio of 0.991:1and subjected to melt polymerization and solid phase polymerization onthe synthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide2A). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 4hours. The above polyamide 2A had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 19.8 μeq/g, an end carboxyl group concentration of 68.6μeq/g and a number average molecular weight of 23000. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 14.4 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 2A alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 2A, and the mixture wasmolten and kneaded with LLDPE to produce a film comprising a singlelayer of the oxygen-absorbing resin composition in the same manners asin Example 1A, except that the temperature in melting and kneading waschanged to 250° C. Further, an oxygen absorption amount and anelongation rate of the above film were measured, and an appearancethereof was observed in the same manners as in Example 1A. The resultsthereof are shown in Table 2A.

Example 5A

Metaxylylenediamine and paraxylylenediamine were mixed in 7:3, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 285° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 3A). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 277° C. and thereaction time to 30 minutes. The above polyamide 3A had Tg of 87° C., amelting point of 255° C., a semi-crystallization time of 18 seconds, anend amino group concentration of 25.8 μeq/g, an end carboxyl groupconcentration of 65.6 μeq/g and a number average molecular weight of18500. MFR could not be measured at 250° C. since it was close to themelting point, and MFR at 260° C. was measured to find that MFR at 260°C. was 29.8 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 3A alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 3A, and the mixture wasmolten and kneaded with LLDPE to produce a film comprising a singlelayer of the oxygen-absorbing resin composition in the same manners asin Example 1A, except that the temperature in melting and kneading waschanged to 265° C. Further, an oxygen absorption amount and anelongation rate of the above film were measured, and an appearancethereof was observed in the same manners as in Example 1A. The abovefilm was a little inferior in an appearance, and line-like unevennesswas observed thereon. The results thereof are shown in Table 2A.

Example 6A

Metaxylylenediamine:adipic acid:isophthalic acid were used in a moleratio of 0.991:0.8:0.2 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 4A). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 215°C. and the polymerization time to 4 hours. The above polyamide 4A had Tgof 92° C., a melting point of 230° C., a semi-crystallization time of250 seconds, an end amino group concentration of 14.8 μeq/g, an endcarboxyl group concentration of 67.2 μeq/g and a number averagemolecular weight of 23000. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 17.4 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 4A alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.07cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4A, and the mixture wasmolten and kneaded with LLDPE to produce a film comprising a singlelayer of the oxygen-absorbing resin composition in the same manners asin Example 1A, except that the temperature in melting and kneading waschanged to 250° C. Further, an oxygen absorption amount and anelongation rate of the above film were measured, and an appearancethereof was observed in the same manners as in Example 1A. The resultsthereof are shown in Table 2A.

Example 7A

Metaxylylenediamine and sebacic acid were used in a mole ratio of0.994:1 and subjected only to melt polymerization on the syntheticconditions described above to synthesize a polyamide resin (hereinafter,the above polyamide resin is referred to as the polyamide 5A). Thedropwise adding time was controlled to 2 hours, and the reaction time inthe melt polymerization was controlled to 1 hour. The above polyamide 5Ahad Tg of 61° C., a melting point of 190° C., a semi-crystallizationtime of 150 seconds, an end amino group concentration of 24.8 μeq/g, anend carboxyl group concentration of 57.2 μeq/g, a number averagemolecular weight of 17200 and MFR of 65.4 g/10 minutes at 240° C. Anon-stretched film was prepared from the resulting polyamide 5A alone,and an oxygen permeability coefficient thereof was determined to findthat it was 1.58 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 5A, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1A toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1A. The results thereof are shown inTable 2A.

Example 8A

Metaxylylenediamine:adipic acid:isophthalic acid were used in a moleratio of 0.998:0.95:0.05 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 6A). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 215°C. and the polymerization time to 20 hours. The above polyamide 6A hadTg of 92° C., a melting point of 230° C., a semi-crystallization time of250 seconds, an end amino group concentration of 28.8 μeq/g, an endcarboxyl group concentration of 61.8 μeq/g, a number average molecularweight of 24200 and MFR of 10.1 g/10 minutes at 240° C. A non-stretchedfilm was prepared from the resulting polyamide 6A alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.08cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6A, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1A toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1A. The results thereof are shown inTable 2A.

Example 9A

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.998:0.6:0.4 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin. Controlled were the dropwise adding time to 2 hours,the reaction time in the melt polymerization to 1 hour, the pressure inan inside of the equipment in the solid phase polymerization to 1 torror less, the polymerization temperature to 150° C. and thepolymerization time to 8 hours. Then, phthalic anhydride 0.2 wt % wasadded thereto, and the mixture was molten and kneaded at 250° C. bymeans of a biaxial extruding equipment to mask an end amino group(hereinafter, the above polyamide resin is referred to as the polyamide7A). The above polyamide 7A had Tg of 70° C., a melting point of 157°C., a semi-crystallization time of 18 seconds, an end amino groupconcentration of 15.8 μeq/g, an end carboxyl group concentration of 51.6μeq/g, a number average molecular weight of 23000 and MFR of 11.4 g/10minutes at 240° C. A non-stretched film was prepared from the resultingpolyamide 7A alone, and an oxygen permeability coefficient thereof wasdetermined to find that it was 0.74 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 7A, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1A toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1A. The results thereof are shown inTable 2A.

Example 10A

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 8A). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 8A had Tg of 78° C., amelting point of 194° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.5 μeq/g, an end carboxylgroup concentration of 81.2 μeq/g, a number average molecular weight of24500 and MFR of 10.5 g/10 minutes at 240° C. A non-stretched film wasprepared from the resulting polyamide 8A alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.21cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 8A, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1A toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1A. The results thereof are shown inTable 2A.

Example 11A

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 9A). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 9A had Tg of 65° C., amelting point of 170° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.2 μeq/g, an end carboxylgroup concentration of 80.0 μeq/g, a number average molecular weight of25200 and MFR of 10.1 g/10 minutes at 240° C. A non-stretched film wasprepared from the resulting polyamide 9A alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.68cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 9A, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1A toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1A. The results thereof are shown inTable 2A.

Example 12A

A film was produced in the same manner as in Example 1A to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1:LLDPE=17:83. The results thereof are shown in Table 2A.

Comparative Example 1A

A film was produced in the same manner as in Example 1A to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1A:LLDPE=80:20. The results thereof are shown in Table 2A.

Comparative Example 2A

A film was produced in the same manner as in Example 1A to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the mixture was not moltenand not kneaded with LLDPE and that the film was prepared only from thecobalt stearate-containing polyamide 1A. The results thereof are shownin Table 2A.

Comparative Example 3A

A film was produced in the same manner as in Example 1A to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1A:LLDPE=10:90. The results thereof are shown in Table 2A.

Comparative Example 4A

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 10A) was synthesized in the same manner as in Example4A, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.998:1 and not subjected to solid phase polymerization. Theabove polyamide 10A had Tg of 78° C., a melting point of 237° C., asemi-crystallization time of 27 seconds, an end amino groupconcentration of 39.1 μeq/g, an end carboxyl group concentration of 70.2μeq/g and a number average molecular weight of 17800. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 51.0 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 10Aalone, and an oxygen permeability coefficient thereof was determined tofind that it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 10A, and the mixturewas kneaded with LLDPE in the same manners as in Example 4A to produce afilm comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1A. The results thereof are shown inTable 2A.

Comparative Example 5A

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 11A) was synthesized in the same manner as in Example4A, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.991:1 and that a polymerization time in the solid phasepolymerization was changed to 2 hours. The above polyamide 11A had Tg of78° C., a melting point of 237° C., a semi-crystallization time of 25seconds, an end amino group concentration of 34.8 μeq/g, an end carboxylgroup concentration of 58.6 μeq/g and a number average molecular weightof 21800. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 18.9 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 11A alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 11A, and the mixturewas kneaded with LLDPE in the same manner as in Example 4A to produce afilm comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1A. The results thereof are shown inTable 2A.

The respective details of the polyamides 1A to 11A obtained above areshown in Table 1A, and the results of the respective examples andcomparative examples are shown in Table 2A.

TABLE 1A Oxygen End amino permeability group Solid MFR coefficientconcentration phase End (g/10 (cc · mm/(m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ Masking³⁾ minutes) day · atm))Polyamide 1A 17.5 MXDA Sebacic acid (0.4) ∘ x 11.0 0.34 (0.992) Adipicacid (0.6) (4 hours) (240° C.) Polyamide 2A 19.8 MXDA Adipic acid (1.0)∘ x 14.4 0.09 (0.991) (4 hours) (250° C.) Polyamide 3A 25.8 MXDA Adipicacid (1.0) x ∘ 29.8 0.13 (0.7) (260° C.) PXDA (0.3) Polyamide 4A 14.8MXDA Adipic acid (0.8) ∘ x 17.4 0.07 (0.991) Isophthalic acid (0.2) (4hours) (250° C.) Polyamide 5A 24.8 MXDA Sebacic acid (1.0) x x 65.4 1.58(0.994) (240° C.) Polyamide 6A 28.8 MXDA Adipic acid (0.95) ∘ x 10.10.08 (0.998) Isophthalic acid (0.05) (20 hours)  (240° C.) Polyamide 7A15.8 MXDA Sebacic acid (0.6) ∘ ∘ 11.4 0.74 (0.998) Adipic acid (0.4) (8hours) (240° C.) Polyamide 8A 19.5 MXDA Sebacic acid (0.3) ∘ x 10.5 0.21(0.992) Adipic acid (0.7) (4 hours) (240° C.) Polyamide 9A 19.2 MXDASebacic acid (0.7) ∘ x 10.1 0.68 (0.992) Adipic acid (0.3) (4 hours)(240° C.) Polyamide 10A 39.1 MXDA Adipic acid (1.0) x x 51.0 0.09(0.998) (250° C.) Polyamide 11A 34.8 MXDA Adipic acid (1.0) ∘ x 18.90.09 (0.999) (2 hours) (250° C.) MXDA: metaxylylenediamine, PXDA:paraxylylenediamine ¹⁾Numerical value in parentheses shows a mole ratioof each component. ²⁾∘: the solid phase polymerization was carried out.The polymerization time is shown in parentheses. x: the solid phasepolymerization was not carried out. ³⁾∘: the end amino group was masked.x: the end amino group was not masked. 4) A non-stretched film wasprepared from the polyamide alone, and an oxygen permeabilitycoefficient thereof was measured at 23° C. and 60% RH.

TABLE 2A Composition Film Polyamide Oxygen absorption (end amino Meltingamount²⁾ group kneading Humidity Humidity Elongation concentrationratio¹⁾ Appearance 100% 30% rate³⁾ Example 1A Polyamide 1A 35:65 Good 27cc 7.8 cc 80% (17.5 μeq/g) Example 2A Polyamide 1A 55:45 Good 25 cc 6.6cc 40% (17.5 μeq/g) Example 3A Polyamide 1A 25:75 Good 24 cc 7.0 cc 82%(17.5 μeq/g) Example 4A Polyamide 2A 35:65 Good 11 cc 1.0 cc 74% (19.8μeq/g) Example 5A Polyamide 3A 35:65 Slightly 13 cc 0.2 cc 75% (25.8μeq/g) inferior Example 6A Polyamide 4A 35:65 Good 17 cc 1.5 cc 77%(14.8 μeq/g) Example 7A Polyamide 5A 35:65 Slightly  6 cc 1.4 cc 62%(24.8 μeq/g) inferior Example 8A Polyamide 6A 35:65 Good 14 cc 1.1 cc74% (28.8 μeq/g) Example 9A Polyamide 7A 35:65 Good 28 cc 8.0 cc 79%(15.8 μeq/g) Example 10A Polyamide 8A 35:65 Good 21 cc 6.1 cc 78% (19.5μeq/g) Example 11A Polyamide 9A 35:65 Good 20 cc 5.8 cc 78% (19.2 μeq/g)Example 12A Polyamide 1 17:83 Good 18 cc 3.8 cc 88% (17.5 μeq/g)Comparative Polyamide 1A 80:20 Good  6 cc 0.8 cc 15% Example 1A (17.5μeq/g) Comparative Polyamide 1A 100:0  Good  4 cc 0.3 cc Film Example 2A(17.5 μeq/g) broken Comparative Polyamide 1A 10:90 Good  3 cc 0.2 cc 84%Example 3A (17.5 μeq/g) Comparative Polyamide 35:65 Inferior  4 cc 0.1cc 63% Example 4A 10A (39.1 μeq/g) Comparative Polyamide 35:65 Good  4cc 0.1 cc 61% Example 5A 11A (34.8 μeq/g) ¹⁾(total weight of transitionmetal catalyst and polyamide resin):weight of polyolefin resin ²⁾wholeamount of oxygen absorbed for 7 days since starting the test ³⁾measuredafter stored at 40° C. and humidity 100% for 1 month

As apparent from Examples 1A to 11A, the oxygen-absorbing resincompositions of the present invention were resin compositions whichshowed an excellent oxygen-absorbing performance at any of high humidityand low humidity and which maintained a film elasticity after absorbingoxygen.

In contrast with this, the film elasticity was notably deteriorated inComparative Examples 1A and 2A in which a content of the polyamide A inthe resin composition exceeded 60% by weight. Further, theoxygen-absorbing performances were unsatisfactory in Comparative Example2A in which the polyolefin resin was not added and Comparative Example3A in which a content of the polyamide A in the resin composition wasless than 15% by weight. In particular, as apparent from comparison ofComparative Examples 1A to 3A with Examples 1A to 3A and 12A, the goodoxygen-absorbing performances were not necessarily obtained when acontent of the polyamide A in the resin composition was large.

On the other hand, in Comparative Example 4A in which a mole ratio ofmetaxylylenediamine to adipic acid was increased as compared withExample 4A and in which the solid phase polymerization was not carriedout and Comparative Example 5A in which a mole ratio ofmetaxylylenediamine to adipic acid was increased and in which the solidphase polymerization time was shortened, an end amino groupconcentration of the polyamide resins obtained exceeded 30 μeq/g, andthe good oxygen-absorbing performances were not obtained. Further, anappearance of the film was deteriorated as well in Comparative Example4A.

Example 12A

A two kind, three layer film (thickness: 10 μm/20 μm/10 μm) in which theoxygen-absorbing resin composition obtained in Example 1A was used for acore layer and in which LLDPE was used for a skin layer was prepared bysubjecting one surface thereof to corona discharge treatment in a widthof 800 mm at 120 m/minute. An appearance of the film thus obtained wasgood, and a HAZE thereof was 74%. A urethane base adhesive for drylaminate (product name: “TM251/CAT-RT88” manufactured by Toyo-Morton,Ltd.) was used for a corona discharge-treated surface to obtain anoxygen-absorbing multilayer film of PET (product name: “E5100”manufactured by Toyobo Co., Ltd., 12)/adhesive (3)/aluminum foil(9)/adhesive (3)/nylon (product name: “N1202” manufactured by ToyoboCo., Ltd., 15)/adhesive (3)/LLDPE (10)/oxygen-absorbing resincomposition (20)/LLDPE (10). Numbers in parentheses mean the thicknesses(unit: μm) of the respective layers. The same shall be shown in thefollowing examples unless otherwise described.

The above oxygen-absorbing multilayer film was used to prepare a threeside-sealed bag of 3×3 cm, and the bag was charged with 10 g of vitaminC powder having a water activity of 0.35 and tightly sealed. Then, itwas stored at 23° C. An oxygen concentration in the bag and anappearance thereof were inspected after stored for one month to findthat an oxygen concentration in the bag was 0.1% or less and that anappearance of the vitamin C tablet was maintained well.

Example 13A A two kind, three layer film was prepared in the same manneras in Example 12A, and this was used to obtain an oxygen-absorbingmultilayer paper base material of bleached craft paper (basis weight:340 g/m²)/urethane base adhesive for dry laminate (product name:“TM251/CAT-RT88” manufactured by Toyo-Morton, Ltd.,3)/aluminum-deposited PET film (product name: “GL-AEH” manufactured byToppan Printing Co., Ltd., 12)/urethane base anchor coating agent(product name: “EL-557A/B” manufactured by Toyo-Morton, Ltd., 0.5)/lowdensity polyethylene (20)/LLDPE (10)/oxygen-absorbing resin composition(20)/LLDPE (10) by extrusion lamination using low density polyethylene(product name: “Milason 18SP” manufactured by Mitsui Chemicals, Inc.).The above base material was molded into a paper container of a gable toptype for 1 liter. A moldability of the container was good. The abovepaper container was charged with rice wine and tightly sealed, and thenit was stored at 23° C. An oxygen concentration in the paper containerwas 0.1% or less after one month, and a flavor of the rice wine wasmaintained well.

Example 14A

An oxygen-absorbing resin composition was obtained in the same manner asin Example 1A, except that an ethylene-propylene block copolymer(product name: “Novatec FG3DC” manufactured by Japan PolypropyleneCorporation, MFR: 9.5 g/10 minutes at 230° C., MFR: 10.6 g/10 minutes at240° C., hereinafter referred to as PP) was used in place of LLDP. Then,a two kind, three layer film (thickness: 15 μm/30 μm/15 μm) was preparedin the same manner as in Example 12A, except that the aboveoxygen-absorbing resin composition was used for a core layer and that PPwas used for a skin layer in place of LLDPE. A HAZE of the film thusobtained was 64%. The urethane base adhesive for dry laminate (productname: “TM251/CAT-RT88” manufactured by Toyo-Morton, Ltd.) was used for acorona discharge-treated surface to obtain an oxygen-absorbingmultilayer film of aluminum-deposited PET (product name: “GL-AEH”manufactured by Toppan Printing Co., Ltd., 12)/adhesive (3)/nylon(product name: “N1202” manufactured by Toyobo Co., Ltd., 15)/adhesive(3)/PP (15)/oxygen-absorbing resin composition (30)/PP (15). The aboveoxygen-absorbing multilayer film was used to prepare a three side-sealedbag of 10×20 cm. A circular vapor-passing port having a diameter of 2 mmwas provided on a part thereof, and a circumference of the vapor-passingport was tentatively adhered by a label seal. The bag was charged withcream stew containing carrot and meat and tightly sealed, and then aftersubjected to retort cooking and thermal sterilization at 124° C. for 30minutes, it was stored at 23° C. The stew in an inside of the bag couldbe visually confirmed. After one month, the bag was heated as it was forabout 4 minutes in an electric oven, and the bag was swollen after about3 minutes to confirm that the tentatively adhered label seal part waspeeled off and that vapor was discharged from the vapor-passing port.After finishing cooking, a flavor of the cream stew and a color tone ofthe carrot were inspected to find that an appearance of the carrot wasmaintained well and that a flavor of the cream stew was good.

Comparative Example 6A

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith LLDPE in a weight ratio of 30:70 to obtain an iron powder baseoxygen-absorbing resin composition AA. A two kind, three layer film wastried to be prepared in the same manner as in Example 12A by using theiron powder base oxygen-absorbing resin composition AA for a core layer,but irregularities of the iron powder were generated on the filmsurface, and the film was not obtained. Accordingly, the iron powderbase oxygen-absorbing resin composition AA was extruded and laminated asan oxygen-absorbing layer in a thickness of 20 μm on LLDPE having athickness of 40 μm to obtain a laminated film which was subjected on anoxygen-absorbing layer surface to corona discharge treatment. The abovelaminated film was laminated on a bleached craft paper in the samemanner as in Example 13A to try to prepare a paper container of a gabletop type comprising an oxygen-absorbing multilayer paper base materialof bleached craft paper (basis weight: 340 g/m²)/urethane base adhesivefor dry laminate (product name: “TM251/CAT-RT88” manufactured byToyo-Morton, Ltd., 3)/aluminum-deposited PET film (product name:“GL-AEH” manufactured by Toppan Printing Co., Ltd., 12)/urethane baseanchor coating agent (product name: “EL-557A/B” manufactured byToyo-Morton, Ltd., 0.5)/low density polyethylene (product name: “Milason18SP” manufactured by Mitsui Chemicals, Inc., 20)/iron powder baseoxygen-absorbing resin composition AA (20)/LLDPE (40), but the thicknesswas large, and it was difficult to prepare a corner of the papercontainer. A preparing speed of the container was reduced to cut off therejected products, and the container was obtained at last. Then, astoring test of rice wine was carried out in the same manner as inExample 13A, but aldehyde odor was generated in opening the container,and a flavor thereof was notably reduced.

Comparative Example 7A

An iron powder base oxygen-absorbing resin composition BA was obtainedin the same manner as in Comparative Example 6A, except that PP was usedin place of LLDPE. Further, a laminated film of the iron powder baseoxygen-absorbing resin composition BA (20)/PP (40) was prepared in thesame manner as in Comparative Example 6A, except that PP was used inplace of LLDPE, and then the oxygen-absorbing layer surface wassubjected to corona discharge treatment. Then, an oxygen-absorbingmultilayer film of aluminum-deposited PET (product name: “GL-AEH”manufactured by Toppan Printing Co., Ltd., 12)/adhesive (3)/nylon(product name: “N1202” manufactured by Toyobo Co., Ltd., 15)/adhesive(3)/iron powder base oxygen-absorbing resin composition BA (20)/PP (40)was obtained in the same manner as in Example 14A. The oxygen-absorbingmultilayer film thus obtained was used to carry out the same test as inExample 14A to result in finding that the flavor was maintained well butthe content could not be visually confirmed and that air bubble-likeunevenness was generated on the surface in heating in an electric oven.

As apparent from Examples 12A to 14A, the oxygen-absorbing resincompositions of the present invention were excellent in a processabilityinto the paper containers and provided storing containers which weregood in storing alcoholic beverages and heating and cooking in anelectric oven even if a vapor-passing port was mounted. Further, theyhad an inside visibility, and a color tone of the content could beconfirmed.

In the present invention, the specific polyamide resin and thetransition metal catalyst were blended with the polyolefin resin in aspecific proportion, whereby provided were the oxygen-absorbing resincompositions which were excellent in an oxygen-absorbing performance atany of a high humidity and a low humidity and maintained the resinstrength after stored and which were excellent in a processability andcould be applied to various containers and uses.

Example 1B

Metaxylylenediamine:adipic acid:isophthalic acid were used in a moleratio of 0.992:0.93:0.07 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 1B). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 195°C. and the polymerization time to 4 hours. The polyamide 1B had Tg of92° C., a melting point of 228° C., a semi-crystallization time of 160seconds, an end amino group concentration of 12.1 μeq/g, an end carboxylgroup concentration of 66.6 μeq/g, a number average molecular weight of26200 and MFR of 18 g/10 minutes at 240° C. A non-stretched film wasprepared from the resulting polyamide 1B alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.07cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1B through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1B) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Kernel KF380” manufactured by Japan PolyethyleneCorporation, MFR: 4.0 g/10 minutes (measured according to JIS K7210),MFR: 8.7 g/10 minutes at 240° C., MFR: 10.0 g/10 minutes at 250° C.,hereinafter referred to as LLDPE) as the polyolefin resin in a weightratio of the cobalt stearate-containing polyamide 1B:LLDPE=35:65 toobtain an oxygen-absorbing resin composition. Then, the aboveoxygen-absorbing resin composition was used to obtain a film having athickness of 50 μm and comprising a single layer of the oxygen-absorbingresin composition, and an appearance of the film was observed to findthat an appearance of the film was good. The film was cut into two filmsof 10×10 mm, and each two sheets of the above film were put in agas-barriering bag which comprised an aluminum foil-laminated film andin which a humidity was controlled to 100% together with 300 ml of air.The bag was tightly sealed and stored at 23° C. and a humidity of 100%to measure an amount of oxygen absorbed for 7 days since startingstorage. Further, an elongation rate of the film after one month passedsince starting storage was measured. The results thereof are shown inTable 1B.

Example 2B

A film was produced in the same manner as in Example 1B to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1B:LLDPE=55:45. The results thereof are shown in Table 1B.

Example 3B

A film was produced in the same manner as in Example 1B to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1B:LLDPE=25:75. The results thereof are shown in Table 1B.

Comparative Example 1B

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2B) was synthesized in the same manner as in Example1B, except that the solid phase polymerization was not carried out. Theabove polyamide 2B had Tg of 90° C., a melting point of 229° C., asemi-crystallization time of 148 seconds, an end amino groupconcentration of 43.5 μeq/g, an end carboxyl group concentration of 66.6μeq/g and a number average molecular weight of 17992. MFR at 240° C. wasmeasured to find that it was 24.4 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 2B alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.07cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 2B, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1B toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1B. The results thereof are shown inTable 1B.

Comparative Example 2B

A film was produced in the same manner as in Example 1B to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1B:LLDPE=80:20. The results thereof are shown in Table 1B.

Comparative Example 3B

A film was produced in the same manner as in Example 1B to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the mixture was not moltenand not kneaded with LLDPE and that the film was prepared only from thecobalt stearate-containing polyamide 1B. The results thereof are shownin Table 1B.

TABLE 1B Polyamide Composition Film End amino group Melting Oxygenconcentration kneading absorption Elongation (μeq/g) ratio¹⁾ aamount²⁾rate³⁾ Example 1B 12.1 35:65 18 cc 80% Example 2B 12.1 55:45 19 cc 40%Example 3B 12.1 25:75 16 cc 60% Comparative 43.5 35:65  3 cc 80% Example1B Comparative 12.1 80:20 12 cc 15% Example 2B Comparative 12.1 100:0 10 cc Film Example 3B broken ¹⁾(total weight of transition metalcatalyst and polyamide resin):weight of polyolefin resin ²⁾whole amountof oxygen absorbed for 7 days since starting the test ³⁾measured afterstored at 40° C. and a humidity 100% for 1 month

As apparent from Examples 1B to 3B, the oxygen-absorbing resincompositions of the present invention were oxygen-absorbing resincompositions which showed a good oxygen-absorbing performance and whichprovided the films with an elasticity maintained after absorbing oxygen.On the other hand, the oxygen-absorbing performance was inferior inComparative Example 1B in which an amino group concentration of thepolyamide resin exceeded 30 μeq/g, and the film elasticity wasdeteriorated in Comparative Examples 2B and 3B in which the polyamideresin was excessively blended in the resin composition.

Example 4B

A two kind, three layer film 1 (thickness: 10 μm/20 μm/10 μm) in whichthe oxygen-absorbing resin composition obtained in Example 1B was usedfor a core layer and in which LLDPE was used for a skin layer wasprepared by subjecting one surface thereof to corona discharge treatmentin a width of 800 mm at 120 m/minute. An appearance of the film thusobtained was good, and a HAZE thereof was 74%. The two kind, three layerfilm obtained was used to obtain an oxygen-absorbing multilayer paperbase material of bleached craft paper (basis weight: 340 g/m²)/urethanebase adhesive for dry laminate (product name: “TM251/CAT-RT88”manufactured by Toyo-Morton, Ltd., 3)/aluminum-deposited PET film(product name: “GL-AEH” manufactured by Toppan Printing Co., Ltd.,12)/urethane base anchor coating agent (product name: “EL-557A/B”manufactured by Toyo-Morton, Ltd., 0.5)/low density polyethylene(20)/LLDPE (10)/oxygen-absorbing resin composition (20)/LLDPE (10) byextrusion lamination using low density polyethylene (product name:“Milason 18SP” manufactured by Mitsui Chemicals, Inc.). The above basematerial was molded into a paper container of a gable top type for 1liter. A moldability of the container was good. The above papercontainer was charged with rice wine and tightly sealed, and then it wasstored at 23° C. An oxygen concentration in the paper container was 0.1%or less after one month, and a flavor of the rice wine was maintainedwell.

Example 5B

An oxygen-absorbing resin composition was obtained in the same manner asin Example 4B, except that an ethylene-propylene block copolymer(product name: “Novatec FG3DC” manufactured by Japan PolypropyleneCorporation, MFR: 9.5 g/10 minutes at 230° C., MFR: 10.6 g/10 minutes at240° C., hereinafter referred to as PP) was used in place of LLDPE.Then, a two kind, three layer film 2 (thickness: 15 μm/30 μm/15 μm) wasprepared in the same manner as in Example 4B, except that the aboveoxygen-absorbing resin composition was used for a core layer and that PPwas used for a skin layer in place of LLDPE. A HAZE of the film thusobtained was 64%. The urethane base adhesive for dry laminate (productname: “TM251/CAT-RT88” manufactured by Toyo-Morton, Ltd.) was used forthe corona discharge-treated surface to obtain an oxygen-absorbingmultilayer film of aluminum-deposited PET (product name: “GL-AEH”manufactured by Toppan Printing Co., Ltd., 12)/adhesive (3)/nylon(product name: “N1202” manufactured by Toyobo Co., Ltd., 15)/adhesive(3)/PP (15)/oxygen-absorbing resin composition (30)/PP (15). The aboveoxygen-absorbing multilayer film was used to prepare a three side-sealedbag of 10×20 cm. A circular vapor-passing port having a diameter of 2 mmwas provided on a part thereof, and a circumference of the vapor-passingport was tentatively adhered by a label seal. The bag was charged withpasta sauce containing carrot and meat and tightly sealed, and thenafter subjected to retort cooking and thermal sterilization at 124° C.for 30 minutes, it was stored at 23° C. The stew in an inside of the bagcould be visually confirmed. After one month, the bag was heated as itwas for about 4 minutes in an electric oven, and the bag was swollenafter about 3 minutes to confirm that the tentatively adhered label sealpart was peeled off and that vapor was discharged from the vapor-passingport. After finishing cooking, a flavor of the pasta sauce and a colortone of the carrot were inspected to find that an appearance of thecarrot was maintained well.

Comparative Example 4B

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith LLDPE in a weight ratio of 35:65 to obtain an iron powder baseoxygen-absorbing resin composition AB. A two kind, three layer film wastried to be prepared in the same manner as in Example 4B by using theiron powder base oxygen-absorbing resin composition AB for a core layer,but irregularities of the iron powder were generated on the filmsurface, and the film was not obtained. Accordingly, the iron powderbase oxygen-absorbing resin composition AB was extruded and laminated asan oxygen-absorbing layer in a thickness of 20 μm on LLDPE having athickness of 40 μm to obtain a laminated film which was subjected on anoxygen-absorbing layer surface to corona discharge treatment. The abovelaminated film was laminated on a bleached craft paper in the samemanner as in Example 5B to try to prepare a paper container of a gabletop type comprising an oxygen-absorbing multilayer paper base materialof bleached craft paper (basis weight: 340 g/m²)/urethane base adhesivefor dry laminate (product name: “TM251/CAT-RT88” manufactured byToyo-Morton, Ltd., 3)/aluminum-deposited PET film (product name:“GL-AEH” manufactured by Toppan Printing Co., Ltd., 12)/urethane baseanchor coating agent (product name: “EL-557A/B” manufactured byToyo-Morton, Ltd., 0.5)/low density polyethylene (product name: “Milason18SP” manufactured by Mitsui Chemicals, Inc., 20)/iron powder baseoxygen-absorbing resin composition AB (20)/LLDPE (40), but the thicknesswas large, and it was difficult to prepare a corner of the papercontainer. A preparing speed of the container was reduced to cut off therejected products, and the container was obtained at last. Then, astoring test of rice wine was carried out in the same manner as inExample 4B, but aldehyde odor was generated in opening the container,and a flavor thereof was notably reduced.

Comparative Example 5B

An iron powder base oxygen-absorbing resin composition BB was obtainedin the same manner as in Comparative Example 4B, except that PP was usedin place of LLDPE. Further, a laminated film of the iron powder baseoxygen-absorbing resin composition BB (20)/PP (40) was prepared in thesame manner as in Comparative Example 4B, except that PP was used inplace of LLDPE, and then the oxygen-absorbing layer surface wassubjected to corona discharge treatment. An oxygen-absorbing multilayerfilm of aluminum-deposited PET (product name: “GL-AEH” manufactured byToppan Printing Co., Ltd., 12)/adhesive (3)/nylon (product name: “N1202”manufactured by Toyobo Co., Ltd., 15)/adhesive (3)/iron powder baseoxygen-absorbing resin composition BB (20)/PP (40) was obtained in thesame manner as in Example 6B. The oxygen-absorbing multilayer film thusobtained was used to carry out the same test as in Example 5B to resultin finding that the flavor was maintained well but the content could notbe visually confirmed and that air bubble-like unevenness was generatedon the surface in heating in an electric oven.

As apparent from Examples 4B to 5B, the oxygen-absorbing resincompositions of the present invention were excellent in a processabilityinto the paper containers and provided storing containers which werefavorable in storing alcoholic beverages and heating and cooking by anelectric oven even if a vapor-passing port was mounted. Further, theyhad an inside visibility, and a color tone of the content could beconfirmed.

In the present invention, the specific polyamide resin and thetransition metal catalyst were blended with the polyolefin resin in aspecific proportion, whereby provided were the oxygen-absorbing resincompositions which were excellent in an oxygen-absorbing performance ata low humidity and a high humidity and maintained a resin strength afterstored and which were excellent in a processability and could be appliedto various containers and uses.

Example 1C

Metaxylylenediamine and paraxylylenediamine were mixed in 7:3, and theabove diamines and adipic acid were used in a mole proportion of 0.993:1and subjected to the melt polymerization and the solid phasepolymerization each described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide1C). Controlled were the dropwise adding time to 2 hours, thepolymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 277° C. and thereaction time to 30 minutes. The above polyamide 1C had Tg of 87° C., amelting point of 259° C., a semi-crystallization time of 18 seconds, anend amino group concentration of 15.8 μeq/g, an end carboxyl groupconcentration of 66.8 μeq/g and a number average molecular weight of21500. Further, MFR at 280° C. was measured to find that MFR at 280° C.was 12.8 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 1C alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1C through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1C) of the polyamide and cobalt stearatewas molten and kneaded at 280° C. with linear low density polyethylene(product name: “Kernel KF380” manufactured by Japan PolyethyleneCorporation, MFR: 4.0 g/10 minutes (measured according to JIS K7210),MFR: 8.7 g/10 minutes at 240° C., MFR: 10.0 g/10 minutes at 250° C.,hereinafter referred to as LLDPE) as the polyolefin resin in a weightratio of the cobalt stearate-containing polyamide 1C:LLDPE=35:65 toobtain an oxygen-absorbing resin composition. Then, the aboveoxygen-absorbing resin composition was used to obtain a film having athickness of 50 μm and comprising a single layer of the oxygen-absorbingresin composition, and an appearance of the film was observed to findthat an appearance of the film was good. The film was cut into two filmsof 10×10 mm, and each two sheets of the above film were put in agas-barriering bag which comprised an aluminum foil-laminated film andin which a humidity was controlled to 100% together with 300 ml of air.The bag was tightly sealed and stored at 23° C. to measure a wholeamount of oxygen absorbed for 7 days after tightly sealed. On the otherhand, an elongation rate of the film after stored at 40° C. and ahumidity of 100% for one month was measured. The results thereof areshown in Table 1C.

Example 2C

A film was produced in the same manner as in Example 1C to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1C:LLDPE=55:45. The results thereof are shown in Table 1C.

Example 3C

A film was produced in the same manner as in Example 1C to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1C:LLDPE=25:75. The results thereof are shown in Table 1C.

Comparative Example 1C

A film was produced in the same manner as in Example 1C to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1C:LLDPE=80:20. The results thereof are shown in Table 1C.

Comparative Example 2C

A film was produced in the same manner as in Example 1C to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the mixture was not moltenand not kneaded with LLDPE and that the film was prepared only from thecobalt stearate-containing polyamide 1C. The results thereof are shownin Table 1C.

Comparative Example 3C

A film was produced in the same manner as in Example 1C to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1C:LLDPE=10:90. The results thereof are shown in Table 1C.

Comparative Example 4C

Metaxylylenediamine and paraxylylenediamine were mixed in 7:3, and theabove diamines and adipic acid were used in a mole proportion of 0.999:1and not subjected to solid phase polymerization to synthesize apolyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2C). The above polyamide 2C had Tg of 78° C., a meltingpoint of 237° C., a semi-crystallization time of 27 seconds, an endamino group concentration of 39.1 μeq/g, an end carboxyl groupconcentration of 70.2 μeq/g and a number average molecular weight of17800. MFR at 250° C. was 51 g/10 minutes.

Then, cobalt stearate was added to the polyamide 2C, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1C toproduce a film comprising a single layer of the oxygen-absorbing resincomposition, except that the temperature in melting and kneading waschanged to 250° C. Further, an oxygen absorption amount and anelongation rate of the above film were measured, and an appearancethereof was observed in the same manners as in Example 1C. The resultsthereof are shown in Table 1C.

TABLE 1C Polyamide Com- End amino position Film group Melting OxygenElon- concentration kneading Appear- absorption gation (μeq/g) ratio¹⁾ance amount²⁾ rate³⁾ Example 1C 15.8 35:65 Good 25 cc 80% Example 2C15.8 55:45 Good 16 cc 40% Example 3C 15.8 25:75 Good 19 cc 82%Comparative 15.8 80:20 Good  6 cc 15% Example 1C Comparative 15.8 100:0 Good  4 cc Film Example 2C broken Comparative 15.8 10:90 Good  3 cc 84%Example 3C Comparative 39.1 35:65 Inferior  4 cc 61% Example 4C ¹⁾(totalweight of transition metal catalyst and polyamide resin):weight ofpolyolefin resin ²⁾whole amount of oxygen absorbed for 7 days sincestarting the test ³⁾measured after stored at 40° C. and a humidity 100%for 1 month

As apparent from Examples 1C to 3C, the oxygen-absorbing resincompositions of the present invention were resin compositions whichshowed an excellent oxygen-absorbing performance and which maintained afilm elasticity after absorbing oxygen.

In contrast with this, the oxygen-absorbing performance wasunsatisfactory in Comparative Examples 1C and 2C in which a content ofthe polyolefin resin in the resin composition exceeded 60% by weight andComparative Example 3C in which the above content was less than 15% byweight. In particular, as apparent from comparison of ComparativeExamples 1C and 2C with Examples 1C to 3C, the good oxygen-absorbingperformances were not necessarily obtained when a content of thepolyamide A in the resin composition was large.

On the other hand, in Comparative Example 4C in which the solid phasepolymerization was not carried out, the end amino group concentrationexceeded 30 μeq/g, and the good oxygen-absorbing performance was notobtained in comparison with Example 1C. Further, an appearance of thefilm was deteriorated as well in Comparative Example 4C.

Example 4C

A four kind, six layer multilayer sheet-molding apparatus comprisingfirst to fourth extruding equipments, a feed block, a T die, a coolingroll and a sheet receiving equipment was used to extrude the componentsfrom the respective extruding equipments, wherein extruded werepolypropylene 1 from the first extruding equipment, the oxygen-absorbingresin prepared in Examples 1C from the second extruding equipment, MXD6(product name: S7007 manufactured by Mitsubishi Gas Chemical Company,Inc., hereinafter referred to as MXD6) from the third extrudingequipment and a polypropylene base adhesive resin (product name: ModecP604V manufactured by Mitsubishi Chemical Corporation) from the fourthextruding equipment, whereby an oxygen-absorbing multilayer sheet wasobtained. The constitution of the above multilayer sheet waspolypropylene 1 (100)/oxygen-absorbing resin layer (100)/adhesive layer(15)/MDX6 layer (30)/adhesive layer (15)/polypropylene 1 (250) from theinner layer. The multilayer sheet prepared by co-extrusion was amultilayer sheet which was free from thickness unevenness and the likeand had a good appearance.

Next, the multilayer sheet thus obtained was subjected to thermoformingprocessing into a cup-like container (inner volume: 70 cc, surface area:120 cm²) with the inner layer turned to an inside by means of a vacuummolding machine. The oxygen-absorbing multilayer container obtained wasfree from thickness unevenness and had a good appearance. The abovecontainer was charged with 60 g of tuna and tightly sealed by using as atop film, a gas-barriering film (PET film (12)/adhesive (3)/aluminumfoil (7)/adhesive (3)/non-stretched polypropylene film (60)) prepared bydry-laminating a PET film (product name: E5102 manufactured by ToyoboCo., Ltd.), an aluminum foil and a non-stretched polypropylene film(product name: Aroma-UT21 manufactured by Okamoto Industries,Incorporated.) by a urethane base adhesive (product name: “TM251”manufactured by Toyo-Morton, Ltd.). The packaged container was subjectedto retort treatment at 125° C. for 25 minutes and stored under theconditions of 25° C. and 60% RH, and it was opened after measuring anoxygen concentration in an inside of the container in the third month toconfirm a flavor and a color tone of the tuna. An oxygen concentrationin an inside of the container was maintained at 0.1% or less, and bothof a flavor and a color tone of the tuna were good.

In the present invention, the specific polyamide resin and thetransition metal catalyst were blended with the polyolefin resin in aspecific proportion, whereby provided were the oxygen-absorbing resincompositions which were excellent in an oxygen-absorbing performance atany of a high humidity and a low humidity and maintained a resinstrength after stored and which were excellent in a processability andcould be applied to various containers and uses.

Example 1D

Metaxylylenediamine:adipic acid were used in a mole ratio of 0.994:1.000and subjected to melt polymerization and solid phase polymerization onthe synthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide1D). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 4hours. The above polyamide 1D had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 14.8 μeq/g, an end carboxyl group concentration of 58.6μeq/g and a number average molecular weight of 23500. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 12.4 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 1D alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1D through a side feed by means a biaxial extruding equipmentso that a cobalt concentration was 400 ppm. Further, the resultingmixture (hereinafter referred to as the cobalt stearate-containingpolyamide 1D) of the polyamide and cobalt stearate was molten andkneaded at 240° C. with linear low density polyethylene (product name:“Kernel KF380” manufactured by Japan Polyethylene Corporation, MFR: 4.0g/10 minutes (measured according to JIS K7210), MFR: 8.7 g/10 minutes at240° C., MFR: 10.0 g/10 minutes at 250° C., hereinafter referred to asLLDPE) as a polyolefin resin in a weight ratio of the cobaltstearate-containing polyamide 1D:LLDPE=35:65 to obtain anoxygen-absorbing resin composition. Then, the above oxygen-absorbingresin composition was used to obtain a film having a thickness of 50 μmand comprising a single layer of the oxygen-absorbing resin composition,and an appearance of the film was observed to find that an appearance ofthe film was good. The film was cut into two films of 10×10 mm, and eachtwo sheets of the above film were put in a gas-barriering bag whichcomprised an aluminum foil-laminated film and in which a humidity wascontrolled to 100% together with 300 ml of air. The bag was tightlysealed and stored at 23° C. and a humidity of 100% to measure an amountof oxygen absorbed for 7 days since starting storage. Further, anelongation rate of the film after one month passed since startingstorage was measured. The results thereof are shown in Table 1D.

Example 2D

A film was produced in the same manner as in Example 1D to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1D:LLDPE=55:45. The results thereof are shown in Table 1D.

Example 3D

A film was produced in the same manner as in Example 1D to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1D:LLDPE=25:75. The results thereof are shown in Table 1D.

Comparative Example 1D

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2D) was synthesized in the same manner as in Example1D, except that the solid phase polymerization was not carried out. Theabove polyamide 2D had an end amino group concentration of 43.5 μeq/g,an end carboxyl group concentration of 66.6 μeq/g and a number averagemolecular weight of 17200. MFR at 250° C. was measured to find that itwas 32.4 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 2D alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 2D, and the mixture wasmolten and kneaded with LLDPE in the same manner as in Example 1D toproduce a film comprising a single layer of the oxygen-absorbing resincomposition, except that the temperature in melting and kneading waschanged to 250° C. Further, an oxygen absorption amount and anelongation rate of the above film were measured, and an appearancethereof was observed in the same manners as in Example 1D. The resultsthereof are shown in Table 1D.

Comparative Example 2D

A film was produced in the same manner as in Example 1D to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1D:LLDPE=80:20. The results thereof are shown in Table 1D.

Comparative Example 3D

A film was produced in the same manner as in Example 1D to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the mixture was not moltenand not kneaded with LLDPE and that the film was prepared only from thecobalt stearate-containing polyamide 1D. The results thereof are shownin Table 1D.

Example 4D

A film was produced in the same manner as in Example 1D to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1D:LLDPE=15:85. The results thereof are shown in Table 1D.

TABLE 1D Polyamide resin Com- End amino position Film group MeltingOxygen Elon- concentration kneading Appear- absorption gation (μeq/g)ratio¹⁾ ance amount²⁾ rate³⁾ Example 1D 14.8 35:65 Good 15 cc 80%Example 2D 14.8 55:45 Good 10 cc 40% Example 3D 14.8 25:75 Good 12 cc82% Example 4D 14.8 15:85 Good  9 cc 81% Comparative 43.5 35:65 Inferior 5 cc 78% Example 1D Comparative 14.8 80:20 Good  4 cc  5% Example 2DComparative 14.8 100:0  Good  3 cc Film Example 3D broken ¹⁾(totalweight of transition metal catalyst and polyamide resin):weight ofpolyolefin resin ²⁾whole amount of oxygen absorbed for 7 days sincestarting the test ³⁾measured after stored at 40° C. and a humidity 100%for 1 month

As apparent from Examples 1D to 4D, the oxygen-absorbing resincompositions of the present invention were oxygen-absorbing resincompositions which showed a good oxygen-absorbing performance and whichmaintained a films elasticity after absorbing oxygen. On the other hand,the oxygen-absorbing performance was inferior in Comparative Example 1Din which an amino group concentration of the polyamide resin exceeded 30μeq/g. In Comparative Examples 2D and 3D in which the polyamide resinwas excessively blended in the resin composition, the oxygen absorptionamount was low, and in addition thereto, the film elasticity wasdeteriorated.

Example 5D

A two kind, three layer film 1 (thickness: 10 μm/20 μm/10 μm) in whichthe oxygen-absorbing resin composition obtained in Example 1D was usedfor a core layer and in which LLDPE was used for a skin layer wasprepared by subjecting one surface thereof to corona discharge treatmentin a width of 800 mm at 120 m/minute. An appearance of the film thusobtained was good, and a HAZE thereof was 24%. The two kind, three layerfilm obtained was used to obtain an oxygen-absorbing multilayer paperbase material of bleached craft paper (basis weight: 340 g/m²)/urethanebase adhesive for dry laminate (product name: “TM251/CAT-RT88”manufactured by Toyo-Morton, Ltd., 3)/aluminum-deposited PET film(product name: “GL-AEH” manufactured by Toppan Printing Co., Ltd.,12)/urethane base anchor coating agent (product name: “EL-557A/B”manufactured by Toyo-Morton, Ltd., 0.5)/low density polyethylene(20)/LLDPE (10)/oxygen-absorbing resin composition (20)/LLDPE (10) byextrusion lamination using low density polyethylene (product name:“Milason 18SP” manufactured by Mitsui Chemicals, Inc.). The above basematerial was molded into a paper container of a gable top type for 1liter. A moldability of the container was good. The above papercontainer was charged with distilled spirit and tightly sealed, and thenit was stored at 23° C. An oxygen concentration in the paper containerwas 0.1% or less after one month, and a flavor of the distilled spiritwas maintained well.

Example 6D

An oxygen-absorbing resin composition was obtained in the same manner asin Example 1D, except that an ethylene-propylene block copolymer(product name: “Novatec FG3DC” manufactured by Japan PolypropyleneCorporation, MFR: 9.5 g/10 minutes at 230° C., MFR: 10.6 g/10 minutes at240° C., hereinafter referred to as PP) was used in place of LLDP. Then,a two kind, three layer film 2 (thickness: 15 μm/30 μm/15 μm) wasprepared in the same manner as in Example 5D, except that the aboveoxygen-absorbing resin composition was used for a core layer and that PPwas used for a skin layer in place of LLDPE. A HAZE of the film thusobtained was 34%. The adhesive for urethane base dry laminate (tradename: “TM251/CAT-RT88” manufactured by Toyo-Morton, Ltd.) was used forthe corona discharge-treated surface to obtain an oxygen-absorbingmultilayer film of aluminum-deposited PET (product name: “GL-AEH”manufactured by Toppan Printing Co., Ltd., 12)/adhesive (3)/nylon(product name: “N1202” manufactured by Toyobo Co., Ltd., 15)/adhesive(3)/PP (15)/oxygen-absorbing resin composition (30)/PP (15). The aboveoxygen-absorbing multilayer film was used to prepare a three side-sealedbag of 10×20 cm. A circular vapor-passing port having a diameter of 2 mmwas provided on a part thereof, and a circumference of the vapor-passingport was tentatively adhered by a label seal. The bag was charged withpasta sauce containing carrot and meat and tightly sealed, and aftersubjected to retort cooking and thermal sterilization at 124° C. for 30minutes, it was stored at 23° C. The pasta sauce in an inside of the bagcould be visually confirmed. After one month, the bag was heated as itwas for about 4 minutes in an electric oven, and the bag was swollenafter about 3 minutes to confirm that the tentatively adhered label sealwas peeled off and that vapor was discharged from the vapor-passingport. After finishing cooking, a flavor of the pasta sauce and a colortone of the carrot were inspected to find that an appearance of thecarrot was maintained well.

Comparative Example 4D

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith LLDPE in a weight ratio of 35:65 to obtain an iron powder baseoxygen-absorbing resin composition AD. A two kind, three layer film wastried to be prepared in the same manner as in Example 5D by using theiron powder base oxygen-absorbing resin composition AD for a core layer,but irregularities of the iron powder were generated on a film surface,and the film was not obtained. Accordingly, the iron powder baseoxygen-absorbing resin composition AD was extruded and laminated as anoxygen-absorbing layer in a thickness of 20 μm on LLDPE having athickness of 40 μm to obtain a laminated film which was subjected on anoxygen-absorbing layer surface to corona discharge treatment. The abovelaminated film was laminated on a bleached craft paper in the samemanner as in Example 5D to try to prepare a paper container of a gabletop type comprising an oxygen-absorbing multilayer paper base materialof bleached craft paper (basis weight: 340 g/m²)/urethane base adhesivefor dry laminate (product name: “TM251/CAT-RT88” manufactured byToyo-Morton, Ltd., 3)/aluminum-deposited PET film (product name:“GL-AEH” manufactured by Toppan Printing Co., Ltd., 12)/urethane baseanchor coating agent (product name: “EL-557A/B” manufactured byToyo-Morton, Ltd., 0.5)/low density polyethylene (product name: “Milason18SP” manufactured by Mitsui Chemicals, Inc., 20)/iron powder baseoxygen-absorbing resin composition AD (20)/LLDPE (40), but the thicknesswas large, and it was difficult to prepare a corner of the papercontainer. A preparing speed of the container was reduced to cut off therejected products, and the container was obtained at last. A storingtest of distilled spirit was carried out in the same manner as inExample 5D, but aldehyde odor was generated in opening the container,and a flavor thereof was notably reduced.

Comparative Example 5D

An iron powder base oxygen-absorbing resin composition BD was obtainedin the same manner as in Comparative Example 4D, except that PP was usedin place of LLDPE. Further, a laminated film of the iron powder baseoxygen-absorbing resin composition BD (20)/PP (40) was prepared in thesame manner as in Comparative Example 4D, except that PP was used inplace of LLDPE, and then the oxygen-absorbing layer surface wassubjected to corona discharge treatment. An oxygen-absorbing multilayerfilm of aluminum-deposited PET (product name: “GL-AEH” manufactured byToppan Printing Co., Ltd., 12)/adhesive (3)/nylon (product name: “N1202”manufactured by Toyobo Co., Ltd., 15)/adhesive (3)/iron powder baseoxygen-absorbing resin composition BD (20)/PP (40) was obtained in thesame manner as in Example 6D. The oxygen-absorbing multilayer film thusobtained was used to carry out the same test as in Example 6D to resultin finding that the flavor was maintained well but the content could notbe visually confirmed and that air bubble-like unevenness was generatedon the surface in heating in an electric oven.

As apparent from Examples 5D to 6D, the oxygen-absorbing resincompositions of the present invention were excellent in a processabilityinto the paper containers and provided the storing containers which weregood in storing alcoholic beverages and heating and cooking in anelectric oven even if a vapor-passing port was mounted. Further, theyhad an inside visibility, and a color tone of the content could beconfirmed.

In the present invention, the specific polyamide resin and thetransition metal catalyst were blended with the polyolefin resin in aspecific proportion, whereby provided were the oxygen-absorbing resincompositions which were excellent in an oxygen-absorbing performance ata low humidity and a high humidity and maintained a resin strength afterstored and which were excellent in a processability and could be appliedto various containers and uses.

Example 1E

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.996:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin, and then an end amino group concentration thereof wasmeasured (the end amino group concentration was 33.6 μeq/g). Next,phthalic anhydride was added thereto as an end masking agent in anamount of 1.5 equivalent based on the above end amino groupconcentration. Then, the mixture was molten and kneaded at 200° C. bymeans of a biaxial extruding equipment, and the end amino group wasmasked to synthesize a polyamide resin (hereinafter, the above polyamideresin is referred to as the polyamide 1E). Controlled were the dropwiseadding time to 2 hours, the reaction time in the melt polymerization to1 hour, the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 160°C. and the polymerization time to 4 hours. The polyamide 1E had Tg of73° C., a melting point of 184° C., a semi-crystallization time of 2000seconds or longer, an end amino group concentration of 21.5 μeq/g, anend carboxyl group concentration of 64.0 μeq/g, a number averagemolecular weight of 22200 and MFR of 15.0 g/10 minutes at 240° C.Further, a non-stretched film was prepared from the resulting polyamide1E alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.34 cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1E through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1E) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Harmolex NC564A” manufactured by Japan PolyethyleneCorporation, MFR: 3.5 g/10 minutes (measured according to JIS K7210),MFR: 7.5 g/10 minutes at 240° C., MFR: 8.7 g/10 minutes at 250° C.,hereinafter referred to as LLDPE) as a polyolefin resin in a weightratio of the cobalt stearate-containing polyamide 1E:LLDPE=35:65 toobtain an oxygen-absorbing resin composition. Then, the aboveoxygen-absorbing resin composition was used to obtain a film having athickness of 50 μm and comprising a single layer of the oxygen-absorbingresin composition, and an appearance of the film was observed to findthat an appearance of the film was good. The film was cut into two filmsof 10×10 mm, and each two sheets of the above film were put ingas-barriering bags which comprised an aluminum foil-laminated film andin which moisture contents in the bags were 30% and 100% together with300 ml of air, and the bags were tightly sealed. They were stored at 23°C. to measure a whole amount of oxygen absorbed for 7 days after tightlysealed. On the other hand, an elongation rate of the film after storedat 40° C. and a humidity of 100% for one month was measured. The resultsthereof are shown in Table 2E.

Example 2E

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2E) was synthesized in the same manner as in Example1E, except that succinic anhydride was used as the end masking agent inplace of phthalic anhydride. The polyamide 1E had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 22.0 μeq/g, an end carboxylgroup concentration of 63.8 μeq/g, a number average molecular weight of21800 and MFR of 16.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 2E alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 2E, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Example 3E

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 3E) was synthesized in the same manner as in Example1E, except that trimellitic anhydride was used as the end masking agentin place of phthalic anhydride. The polyamide 3E had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 21.8 μeq/g, an end carboxylgroup concentration of 65.0 μeq/g, a number average molecular weight of22000 and MFR of 15.5 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 3E alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 3E, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Example 4E

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.999:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin, and then an end amino group concentration thereof wasmeasured (the end amino group concentration was 35.8 μeq/g). Next,phthalic anhydride was added thereto as an end masking agent in anamount of 0.2 equivalent based on the above end amino groupconcentration. Then, the mixture was molten and kneaded at 200° C. bymeans of a biaxial extruding equipment, and the end amino group wasmasked to synthesize a polyamide resin (hereinafter, the above polyamideresin is referred to as the polyamide 4E). Controlled were the dropwiseadding time to 2 hours, the reaction time in the melt polymerization to1 hour, the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 160°C. and the polymerization time to 4 hours. The polyamide 4E had Tg of73° C., a melting point of 184° C., a semi-crystallization time of 2000seconds or longer, an end amino group concentration of 29.2 μeq/g, anend carboxyl group concentration of 52.8 μeq/g, a number averagemolecular weight of 24000 and MFR of 11.2 g/10 minutes at 240° C.Further, a non-stretched film was prepared from the resulting polyamide4E alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.34 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4E, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Example 5E

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 5E) was synthesized in the same manner as in Example4E, except that an addition amount of phthalic anhydride was changed to4.0 equivalent based on the end amino group concentration after thesolid phase polymerization. The polyamide 5E had Tg of 73° C., a meltingpoint of 184° C., a semi-crystallization time of 2000 seconds or longer,an end amino group concentration of 13.5 μeq/g, an end carboxyl groupconcentration of 53.8 μeq/g, a number average molecular weight of 19700and MFR of 35.0 g/10 minutes at 240° C. Further, a non-stretched filmwas prepared from the resulting polyamide 5E alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 5E, and the mixture wasmolten and kneaded with LLDPE in the same manner as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Example 6E

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 6E) was synthesized in the same manner as in Example4E, except that an addition amount of phthalic anhydride was changed to5.0 equivalent based on the end amino group concentration after thesolid phase polymerization. The polyamide 6E had Tg of 73° C., a meltingpoint of 184° C., a semi-crystallization time of 2000 seconds or longer,an end amino group concentration of 11.5 μeq/g, an end carboxyl groupconcentration of 52.8 μeq/g, a number average molecular weight of 18100and MFR of 50.1 g/10 minutes at 240° C. Further, a non-stretched filmwas prepared from the resulting polyamide 6E alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6E, and the mixture wasmolten and kneaded with LLDPE in the same manner as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Example 7E

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 1.0:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin, and then an end amino group concentration thereof wasmeasured (the end amino group concentration was 37.7 μeq/g). Next,phthalic anhydride was added thereto as an end masking ageant in anamount of 1.5 equivalent based on the above end amino groupconcentration. Then, the mixture was molten and kneaded at 220° C. bymeans of a biaxial extruding equipment, and the end amino group wasmasked to synthesize a polyamide resin (hereinafter, the above polyamideresin is referred to as the polyamide 7E). Controlled were the dropwiseadding time to 2 hours, the reaction time in the melt polymerization to1 hour, the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 160°C. and the polymerization time to 4 hours. The polyamide 7E had Tg of78° C., a melting point of 199° C., a semi-crystallization time of 2000seconds or longer, an end amino group concentration of 19.5 μeq/g, anend carboxyl group concentration of 50.2 μeq/g, a number averagemolecular weight of 23800 and MFR of 14.1 g/10 minutes at 240° C.Further, a non-stretched film was prepared from the resulting polyamide7E alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.21 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 7E, and the mixture wasmolten and kneaded with LLDPE in the same manner as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Example 8E

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 1.001:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin, and then an end amino group concentration thereof wasmeasured (the end amino group concentration was 38.3 μeq/g). Next,phthalic anhydride was added thereto as an end masking agent in anamount of 1.5 equivalent based on the above end amino groupconcentration. Then, the mixture was molten and kneaded at 200° C. bymeans of a biaxial extruding equipment, and the end amino group wasmasked to synthesize a polyamide resin (hereinafter, the above polyamideresin is referred to as the polyamide 8E). Controlled were the dropwiseadding time to 2 hours, the reaction time in the melt polymerization to1 hour, the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 160°C. and the polymerization time to 4 hours. The polyamide 8E had Tg of66° C., a melting point of 160° C., a semi-crystallization time of 2000seconds or longer, an end amino group concentration of 20.8 μeq/g, anend carboxyl group concentration of 52.2 μeq/g, a number averagemolecular weight of 21500 and MFR of 16.5 g/10 minutes at 240° C.Further, a non-stretched film was prepared from the resulting polyamide8E alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.68 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 8E, and the mixture wasmolten and kneaded with LLDPE in the same manner as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Example 9E

A film was produced in the same manner as in Example 1E to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1E:LLDPE=55:45. The results thereof are shown in Table 2E.

Example 10E

A film was produced in the same manner as in Example 1E to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1E:LLDPE=25:75. The results thereof are shown in Table 2E.

Example 11E

Metaxylylenediamine and paraxylylenediamine were mixed in a moleproportion of 7:3, and the above diamines and adipic acid were used in amole proportion of 1:1 and subjected only to melt polymerization on thesynthetic conditions described above to synthesize a polyamide resin.Then, an end amino group concentration thereof was measured (the endamino group concentration was 43.4 μeq/g). Next, phthalic anhydride wasadded thereto as an end masking agent in an amount of 1.5 equivalentbased on the above end amino group concentration. Then, the mixture wasmolten and kneaded at 285° C. by means of a biaxial extruding equipment,and the end amino group was masked to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide9E). Controlled were the dropwise adding time to 2 hours, thepolymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 277° C. and thereaction time to 30 minutes. The above polyamide 9E had Tg of 87° C., amelting point of 259° C., a semi-crystallization time of 17 seconds, anend amino group concentration of 27.8 μeq/g, an end carboxyl groupconcentration of 64.3 μeq/g and a number average molecular weight of18000. MFR could not be measured at 260° C. since it was close to themelting point, and MFR at 270° C. was measured to find that MFR at 270°C. was 30.3 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 9E alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 9E, and the mixture wasmolten and kneaded with LLDPE in the same manner as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition, except that the temperature in melting and kneading waschanged to 270° C. Further, an oxygen absorption amount and anelongation rate of the above film were measured, and an appearancethereof was observed in the same manners as in Example 1E. The resultsthereof are shown in Table 2E.

Comparative Example 1E

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 10E) was synthesized in the same manner as in Example4E, except that phthalic anhydride was not added and that the end wasnot masked. The polyamide 10E had Tg of 73° C., a melting point of 184°C., a semi-crystallization time of 2000 seconds or longer, an end aminogroup concentration of 35.8 μeq/g, an end carboxyl group concentrationof 49.7 μeq/g, a number average molecular weight of 243000 and MFR of10.0 g/10 minutes at 240° C. Further, a non-stretched film was preparedfrom the resulting polyamide 10E alone, and an oxygen permeabilitycoefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 10E, and the mixturewas molten and kneaded with LLDPE in the same manner as in Example 1E toproduce a film comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Comparative Example 2E

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 11E) was synthesized in the same manner as in Example4E, except that an addition amount of phthalic anhydride was changed to0.1 equivalent based on the end amino group concentration after thesolid phase polymerization. The polyamide 11E had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 31.8 μeq/g, an end carboxylgroup concentration of 49.7 μeq/g, a number average molecular weight of24000 and MFR of 10.6 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 11E alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 11E, and the mixturewas kneaded with LLDPE in the same manner as in Example 1E to produce afilm comprising a single layer of the oxygen-absorbing resincomposition. Further, an oxygen absorption amount and an elongation rateof the above film were measured, and an appearance thereof was observedin the same manners as in Example 1E. The results thereof are shown inTable 2E.

Comparative Example 3E

A film was produced in the same manner as in Example 1E to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide1E:LLDPE=80:20. The results thereof are shown in Table 2E.

Comparative Example 4E

A film was produced in the same manner as in Example 1E to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the mixture was not moltenand not kneaded with LLDPE and that the film was prepared only from thecobalt stearate-containing polyamide 1E. The results thereof are shownin Table 2E.

Comparative Example 5E

A film was produced in the same manner as in Example 1E to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the cobalt stearate-containing polyamide9E:LLDPE=10:90. The results thereof are shown in Table 2E.

The respective details of the polyamides 1E to 11E obtained above areshown in Table 1E, and the results of the respective examples andcomparative examples are shown in Table 2E.

TABLE 1E End masking agent End amino End addition group Solid MFRmasking amount concentration¹⁾ phase (g/10 agent (equivalent) (μeq/g)Diamine²⁾ Dicarboxylic acid²⁾ polymerization³⁾ minutes) Polyamide 1EPhthalic 1.5 21.5 MXDA Sebacic acid (0.4) ∘ 15.0 anhydride (0.996)Adipic acid (0.6) (4 hours) (240° C.) Polyamide 2E Phthalic 1.5 22.0MXDA Sebacic acid (0.4) ∘ 16.1 anhydride (0.996) Adipic acid (0.6) (4hours) (240° C.) Polyamide 3E Trimellitic 1.5 21.8 MXDA Sebacic acid(0.4) ∘ 15.5 anhydride (0.996) Adipic acid (0.6) (4 hours) (240° C.)Polyamide 4E Phthalic 0.2 29.2 MXDA Sebacic acid (0.4) ∘ 11.2 anhydride(0.999) Adipic acid (0.6) (4 hours) (240° C.) Polyamide 5E Phthalic 4.013.5 MXDA Sebacic acid (0.4) ∘ 35.0 anhydride (0.999) Adipic acid (0.6)(4 hours) (240° C.) Polyamide 6E Phthalic 5.0 11.5 MXDA Sebacic acid(0.4) ∘ 50.1 anhydride (0.999) Adipic acid (0.6) (4 hours) (240° C.)Polyamide 7A Phthalic 1.5 19.5 MXDA Sebacic acid (0.3) ∘ 14.0 anhydride(1.0) Adipic acid (0.7) (4 hours) (240° C.) Polyamide 8E Phthalic 1.520.8 MXDA Sebacic acid (0.7) ∘ 16.5 anhydride (1.001) Adipic acid (0.3)(4 hours) (240° C.) Polyamide 9E Phthalic 1.5 27.8 MXDA Adipic acid(1.0) x 30.3 anhydride (0.7) (270° C.) PXDA (0.3) Polyamide 10E End wasnot masked 35.8 MXDA Sebacic acid (0.4) ∘ 10.0 (0.999) Adipic acid (0.6)(4 hours) (240° C.) Polyamide 11E Phthalic 0.1 31.8 MXDA Sebacic acid(0.4) ∘ 10.6 anhydride (0.999) Adipic acid (0.6) (4 hours) (240° C.)MXDA: metaxylylenediamine, PXDA: paraxylylenediamine ¹⁾End amino groupconcentration after masking the end amino group. ²⁾Numerical value inparentheses shows a mole ratio of each component. ³⁾Polymerization timeis shown in parentheses. x: solid phase polymerization was not carriedout.

TABLE 2E Composition Film Polyamide Oxygen absorption (end amino Meltingamount²⁾ group kneading Humidity Humidity Elongation concentrationratio¹⁾ Appearance 100% 30% rate³⁾ Example 1E Polyamide 1E 35:65 Good 32cc 8.5 cc 81% (21.5 μeq/g) Example 2E Polyamide 2E 35:65 Good 30 cc 7.8cc 77% (22.0 μeq/g) Example 3E Polyamide 3E 35:65 Good 28 cc 7.0 cc 75%(21.8 μeq/g) Example 4E Polyamide 4E 35:65 Good 20 cc 4.0 cc 77% (29.2μeq/g) Example 5E Polyamide 5E 35:65 Slightly 17 cc 3.1 cc 70% (13.5μeq/g) inferior Example 6E Polyamide 6E 35:65 Inferior 12 cc 1.0 cc 68%(11.5 μeq/g) Example 7E Polyamide 7E 35:65 Good 21 cc 6.5 cc 78% (19.5μeq/g) Example 8E Polyamide 8E 35:65 Good 20 cc 5.8 cc 77% (20.8 μeq/g)Example 9E Polyamide 1E 55:45 Good 31 cc 7.1 cc 60% (21.5 μeq/g) Example10E Polyamide 1E 25:75 Good 25 cc 6.0 cc 86% (21.5 μeq/g) Example 11EPolyamide 9E 35:65 Slightly 12 cc 1.2 cc 77% (27.8 μeq/g) inferiorComparative Polyamide 35:65 Good  6 cc 0.1 cc 80% Example 1E 10E (35.8μeq/g) Comparative Polyamide 35:65 Good  9 cc 0.7 cc 78% Example 2E 11E(31.8 μeq/g) Comparative Polyamide 1E 80:20 Good  7 cc 0.6 cc 10%Example 3E (21.5 μeq/g) Comparative Polyamide 1E 100:0  Good  8 cc 0.2cc Film Example 4E (21.5 μeq/g) broken Comparative Polyamide 9E 10:90Slightly  2 cc 0.1 cc 83% Example 5E (27.8 μeq/g) inferior ¹⁾(totalweight of transition metal catalyst and polyamide resin):weight ofpolyolefin resin ²⁾whole amount of oxygen absorbed for 7 days sincestarting the test ³⁾measured after stored at 40° C. and humidity 100%for 1 month

As apparent from Examples 1E to 11E, the oxygen-absorbing resincompositions of the present invention were resin compositions whichshowed an excellent oxygen-absorbing performance at any of a highhumidity and a low humidity and which maintained a film elasticity afterabsorbing oxygen.

In contrast with this, in Comparative Examples 1E and 2E in which anaddition amount of the end masking agent was less than 0.5 equivalent,an end amino concentration of the polyamide resins obtained exceeded 30μeq/g, and the good oxygen-absorbing performances were not obtained.

Further, the oxygen-absorbing performances were unsatisfactory inComparative Examples 3E and 4E in which a content of the polyolefinresin in the resin composition exceeded 60% by weight and ComparativeExample 5E in which the content was less than 15% by weight. Inparticular, as apparent from comparison of Comparative Examples 3E to 5Ewith Examples 1E, 9E, 10E and 11E, the good oxygen-absorbingperformances were not necessarily obtained when a content of thepolyamide A in the resin composition was large.

Example 12E

A two kind, three layer film (thickness: 10 μm/20 μm/10 μm) in which theoxygen-absorbing resin composition obtained in Example 1E was used for acore layer and in which LLDPE was used for a skin layer was prepared bysubjecting one surface thereof to corona discharge treatment in a widthof 1000 mm at 120 m/minute. An appearance of the film thus obtained wasgood, and a HAZE thereof was 77%. A urethane base adhesive for drylaminate (product name: “AD817/CAT-RT86L-60” manufactured byToyo-Morton, Ltd.) was used for a corona discharge-treated surface toobtain an oxygen-absorbing multilayer film of PET (product name: “E5100”manufactured by Toyobo Co., Ltd., 12)/adhesive (3)/aluminum foil(9)/adhesive (3)/nylon (product name: “N1202” manufactured by ToyoboCo., Ltd., 15)/adhesive (3)/LLDPE (10)/oxygen-absorbing resincomposition (20)/LLDPE (10).

The above oxygen-absorbing multilayer film was used to prepare a threeside-sealed bag of 4×4 cm, and the bag was charged with 10 g of vitaminC powder having a water activity of 0.35 and tightly sealed. Then, itwas stored at 23° C. After stored for one month, an oxygen concentrationin the bag and an appearance thereof were inspected to find that anoxygen concentration in the bag was 0.1% or less and that an appearanceof the vitamin C tablets was maintained well.

Example 13E

A two kind, three layer film was prepared in the same manner as inExample 12E, and this was used to obtain an oxygen-absorbing multilayerpaper base material of bleached craft paper (basis weight: 340g/m²)/urethane base adhesive for dry laminate (product name:“AD817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.,3)/aluminum-deposited PET film (product name: “GL-ARH-F” manufactured byToppan Printing Co., Ltd., 12)/urethane base anchor coating agent(product name: “EL-557A/B” manufactured by Toyo-Morton, Ltd., 0.5)/lowdensity polyethylene (20)/LLDPE (10)/oxygen-absorbing resin composition(20)/LLDPE (10) by extrusion lamination using low density polyethylene(product name: “Milason 18SP” manufactured by Mitsui Chemicals, Inc.).The above base material was molded into a paper container of a gable toptype for 1 liter. A moldability of the container was good. The abovepaper container was charged with distilled rice spirit and tightlysealed, and then it was stored at 23° C. An oxygen concentration in thepaper container was 0.1% or less after one month, and a flavor of thedistilled rice spirit was maintained well.

Example 14E

An oxygen-absorbing resin composition was obtained in the same manner asin Example 1E, except that an ethylene-propylene block copolymer(product name: “Novatec FG3DC” manufactured by Japan PolypropyleneCorporation, MFR: 9.5 g/10 minutes at 230° C., MFR: 10.6 g/10 minutes at240° C., hereinafter referred to as PP) was used in place of LLDPE.Then, a two kind, three layer film (thickness: 15 μm/30 μm/15 μm) wasprepared in the same manner as in Example 12E, except that the aboveoxygen-absorbing resin composition was used for a core layer and that PPwas used for a skin layer in place of LLDPE. A HAZE of the film thusobtained was 64%. The urethane base adhesive for dry laminate (productname: “AD817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.) was usedfor the corona discharge-treated surface to obtain an oxygen-absorbingmultilayer film of aluminum-deposited PET (product name: “GL-AEH”manufactured by Toppan Printing Co., Ltd., 12)/adhesive (3)/nylon(product name: “N1202” manufactured by Toyobo Co., Ltd., 15)/adhesive(3)/PP (15)/oxygen-absorbing resin composition (30)/PP (15). The aboveoxygen-absorbing multilayer film was used to prepare a three side-sealedbag of 10×20 cm. A circular vapor-passing port having a diameter of 2 mmwas provided on a part thereof, and a circumference of the vapor-passingport was tentatively adhered by a label seal. The bag was charged withcurry containing carrot and meat and tightly sealed, and after subjectedto retort cooking and thermal sterilization at 124° C. for 30 minutes,it was stored at 23° C. The stew in an inside of the bag could bevisually confirmed. After one month, the bag was heated as it was forabout 4 minutes in an electric oven, and the bag was swollen after about3 minutes to confirm that the tentatively adhered label seal was peeledoff and that vapor was discharged from the vapor-passing port. Afterfinishing cooking, a flavor of the curry and a color tone of the carrotwere inspected to find that an appearance of the carrot was maintainedwell and that a flavor of the curry was good.

Comparative Example 6E

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith LLDPE in a weight ratio of 30:70 to obtain an iron powder baseoxygen-absorbing resin composition AE. A two kind, three layer film wastried to be prepared in the same manner as in Example 12E by using theiron powder base oxygen-absorbing resin composition AE for a core layer,but irregularities of the iron powder were generated on the filmsurface, and the film was not obtained. Accordingly, the iron powderbase oxygen-absorbing resin composition AE was extruded and laminated asan oxygen-absorbing layer in a thickness of 20 μm on LLDPE having athickness of 40 μm to obtain a laminated film which was subjected on anoxygen-absorbing layer surface to corona discharge treatment. The abovelaminated film was laminated on a bleached craft paper in the samemanner as in Example 13E to try to prepare a paper container of a gabletop type comprising an oxygen-absorbing multilayer paper base materialof bleached craft paper (basis weight: 340 g/m²)/urethane base adhesivefor dry laminate (product name: “AD817/CAT-RT86L-60” manufactured byToyo-Morton, Ltd., 3)/aluminum-deposited PET film (product name:“GL-ARH” manufactured by Toppan Printing Co., Ltd., 12)/urethane baseanchor coating agent (product name: “EL-557A/B” manufactured byToyo-Morton, Ltd., 0.5)/low density polyethylene (product name: “Milason18SP” manufactured by Mitsui Chemicals, Inc., 20)/iron powder baseoxygen-absorbing resin composition AE (20)/LLDPE (40), but the thicknesswas large, and it was difficult to prepare a corner of the papercontainer. A preparing speed of the container was reduced to cut off therejected products, and the container was obtained at last. A storingtest of distilled rice spirit was carried out in the same manner as inExample 13E, but aldehyde odor was generated in opening the container,and a flavor thereof was notably reduced.

Comparative Example 7E

An iron powder base oxygen-absorbing resin composition BE was obtainedin the same manner as in Comparative Example 6E, except that PP was usedin place of LLDPE. Further, a laminated film of the iron powder baseoxygen-absorbing resin composition BE (20)/PP (40) was prepared in thesame manner as in Comparative Example 6E, except that PP was used inplace of LLDPE, and then the oxygen-absorbing layer surface wassubjected to corona discharge treatment. An oxygen-absorbing multilayerfilm of aluminum-deposited PET (product name: “GL-ARH” manufactured byToppan Printing Co., Ltd., 12)/adhesive (3)/nylon (product name: “N1202”manufactured by Toyobo Co., Ltd., 15)/adhesive (3)/iron powder baseoxygen-absorbing resin composition BE (20)/PP (40) was obtained in thesame manner as in Example 14E. The oxygen-absorbing multilayer film thusobtained was used to carry out the same test as in Example 14E to resultin finding that the flavor was maintained well but the content could notbe visually confirmed and that air bubble-like unevenness was generatedon the surface in heating in an electric oven.

As apparent from Examples 12E to 14E, the oxygen-absorbing resincompositions of the present invention were excellent in a processabilityinto the paper containers and provided storing containers which weregood in storing alcoholic beverages and heating and cooking in anelectric oven even if a vapor-passing port was mounted. Further, theyhad an inside visibility, and a color tone of the content could beconfirmed.

In the present invention, the specific polyamide resin and thetransition metal catalyst were blended with the polyolefin resin in aspecific proportion, whereby provided were the oxygen-absorbing resincompositions which were excellent in an oxygen-absorbing performance atany of a high humidity and a low humidity and maintained a resin with astrength after stored and which were excellent in a processability andcould be applied to various containers and uses.

Production Process for the Oxygen-Absorbing Resin Composition Example 1F

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.993:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1F). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 5 hours. The polyamide 1F had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 15.6 μeq/g, an end carboxylgroup concentration of 64.3 μeq/g, a number average molecular weight of25000 and MFR of 10.6 g/10 minutes at 240° C. The results thereof areshown in Table 1F.

Subsequently, cobalt stearate was added as a transition metal catalystto molten linear low density polyethylene (product name: “Yumerit 4040F”manufactured by Ube Industries, Ltd., MFR: 4.0 g/10 minutes (measuredaccording to JIS K7210), MFR: 7.9 g/10 minutes at 240° C., MFR: 8.7 g/10minutes at 250° C., hereinafter referred to as LLDPE 1) through a sidefeed by means of a biaxial extruding equipment so that a cobaltconcentration was 1000 ppm, whereby a master batch 1 was obtained. Inthe above case, LLDPE 1 was not observed to be reduced in a viscosity.

The above master batch 1 and the polyamide 1F were molten and kneaded at240° C. in a weight ratio of the master batch 1:the polyamide 1F=75:25to obtain an oxygen-absorbing resin composition. Then, the aboveoxygen-absorbing resin composition was used to obtain a film having athickness of 50 μm and comprising a single layer of the oxygen-absorbingresin composition, and an appearance of the film was observed to findthat an appearance of the film was good. The above film was cut into twofilms of 10×10 mm, and the films were put in gas-barriering bags whichcomprised an aluminum foil-laminated film and in which moisture contentsin the bags were 30% and 100% together with 300 ml of air, followed bytightly sealing the bags. They were stored at 23° C. to measure a wholeamount of oxygen absorbed for 7 days after tightly sealed. On the otherhand, an elongation rate of the film after stored at 40° C. and ahumidity of 100% for one month was measured. The results thereof areshown in Table 2F.

Example 2F

A film was produced in the same manner as in Example 1F to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the master batch 1: the polyamide 1F=85:15. Theresults thereof are shown in Table 2F.

Example 3F

A film was produced in the same manner as in Example 1F to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the master batch 1: the polyamide 1F=45:55. Theresults thereof are shown in Table 2F.

Example 4F

Cobalt stearate was added to LLDPE 1 so that a cobalt concentration was400 ppm, whereby a master batch 2 was obtained. In the above case, LLDPE1 was not observed to be reduced in a viscosity. Then, the above masterbatch 2 and the polyamide 1F were molten and kneaded in a weight ratioof the master batch 2:the polyamide 1F=75:25, and a film was produced inthe same manner as in Example 1F to measure an oxygen absorption amountand an elongation rate of the above film and observe an appearancethereof. The results thereof are shown in Table 2F.

Example 5F

Cobalt stearate was added to LLDPE 1 so that a cobalt concentration was2000 ppm, whereby a master batch 3 was obtained. In the above case,LLDPE 1 was not observed to be reduced in a viscosity. Then, the abovemaster batch 3 and the polyamide 1F were molten and kneaded in a weightratio of the master batch 3:the polyamide 1F=75:25, and a film wasproduced in the same manner as in Example 1F to measure an oxygenabsorption amount and an elongation rate of the above film and observean appearance thereof. The results thereof are shown in Table 2F.

Example 6F

Metaxylylenediamine:adipic acid:isophthalic acid were used in a moleratio of 0.991:0.85:0.15 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 2F). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 205°C. and the polymerization time to 5 hours. The above polyamide 2F had Tgof 94° C., a melting point of 226° C., a semi-crystallization time of770 seconds, an end amino group concentration of 11.1 μeq/g, an endcarboxyl group concentration of 70.1 μeq/g and a number averagemolecular weight of 24600. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 14.5 g/10 minutes. The results thereof are shownin Table 1F.

Then, a film was produced in the same manner as in Example 1F to measurean oxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the temperature in meltingand kneading was changed to 250° C. The results thereof are shown inTable 2F.

Example 7F

Metaxylylenediamine:adipic acid were used in a mole ratio of 0.993:1 andsubjected to melt polymerization and solid phase polymerization on thesynthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide3F). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 5hours. The above polyamide 3F had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 12.2 μeq/g, an end carboxyl group concentration of 68.5μeq/g and a number average molecular weight of 24800. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 13.4 g/10 minutes.The results thereof are shown in Table 1F.

Then, a film was produced in the same manner as in Example 1F to measurean oxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the temperature in meltingand kneading was changed to 250° C. The results thereof are shown inTable 2F.

Example 8F

Metaxylylenediamine and paraxylylenediamine were mixed in 85:15, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 270° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 4F). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingthe diamine mixture in the melt polymerization to 270° C. and thereaction time to 30 minutes. The above polyamide 4F had Tg of 83° C., amelting point of 254° C., a semi-crystallization time of 24 seconds, anend amino group concentration of 22.2 μeq/g, an end carboxyl groupconcentration of 69.2 μeq/g and a number average molecular weight of19000. MFR could not be measured at 260° C. since it was close to themelting point, and MFR at 270° C. was measured to find that MFR at 270°C. was 34.6 g/10 minutes. The results thereof are shown in Table 1F.

Then, a film was produced in the same manner as in Example 1F to measurean oxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that the temperature in meltingand kneading was changed to 270° C. The results thereof are shown inTable 2F.

Comparative Example 1F

A film was produced in the same manner as in Example 1F to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the master batch 1: the polyamide 1F=90:10. Theresults thereof are shown in Table 2F.

Comparative Example 2F

A film was produced in the same manner as in Example 1F to measure anoxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof, except that a weight ratio in melting andkneading was changed to the master batch 1: the polyamide 1F=10:90. Theresults thereof are shown in Table 2F.

Comparative Example 3F

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide resin 5F) was synthesized in the same manner as inExample 7F, except that metaxylylenediamine:adipic acid were used in amole ratio of 1:1. The above polyamide resin 5F had Tg of 84° C., amelting point of 237° C., a semi-crystallization time of 25 seconds, anend amino group concentration of 38.9 μeq/g, an end carboxyl groupconcentration of 40.8 μeq/g and a number average molecular weight of25100. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 12.8 g/10 minutes. The results thereof are shown in Table 1F.

Then, the polyamide resin was molten and kneaded with the master batch 1in the same manner as in Example 7F, and a film was produced to measurean oxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof. The results thereof are shown in Table2F.

Comparative Example 4F

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 6F) was synthesized in the same manner as in Example7F, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.993:1 and that a polymerization time in the solid phasepolymerization was changed to 2 hours. The above polyamide 6F had Tg of84° C., a melting point of 237° C., a semi-crystallization time of 25seconds, an end amino group concentration of 31.1 μeq/g, an end carboxylgroup concentration of 84.1 μeq/g and a number average molecular weightof 17400. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 39.2 g/10 minutes. The results thereof are shown in Table 1F.

Then, the polyamide resin was molten and kneaded with the master batch 1in the same manner as in Example 7F, and a film was produced to measurean oxygen absorption amount and an elongation rate of the above film andobserve an appearance thereof. The results thereof are shown in Table2F.

TABLE 1F End amino group Solid MFR concentration phase End (g/10 (μeq/g)Diamine¹⁾ Dicarboxylic acid¹⁾ polymerization²⁾ masking³⁾ minutes)Polyamide 1F 15.6 MXDA Sebacic acid (0.4) Present None 11.0 (0.993)Adipic acid (0.6) (5 hours) (240° C.) Polyamide 2F 11.1 MXDA Adipic acid(0.85) Present None 14.5 (0.991) Isophthalic acid (0.15) (5 hours) (250°C.) Polyamide 3F 12.2 MXDA Adipic acid (1.0) Present None 13.4 (0.993)(5 hours) (250° C.) Polyamide 4F 22.2 MXDA Adipic acid (1.0) NonePresent 34.6 (0.85) (270° C.) PXDA (0.15) Polyamide 5F 38.9 MXDA Adipicacid (1.0) Present None 12.8 (1.0) (5 hours) (250° C.) Polyamide 6F 31.1MXDA Adipic acid (1.0) Present None 39.2 (0.993) (2 hours) (250° C.)MXDA: metaxylylenediamine, PXDA: paraxylylenediamine ¹⁾Numerical valuein parentheses shows a mole ratio of each component. ²⁾Present: thesolid phase polymerization was carried out. The polymerization time isshown in parentheses. None: the solid phase polymerization was notcarried out. ³⁾Present: the end amino group was masked. None: the endamino group was not masked.

TABLE 2F Film Master batch Polyamide Oxygen absorption Co (end aminoMelting Co amount²⁾ concentration group kneading concentration HumidityHumidity Elongation No. (ppm) concentration ratio¹⁾ (ppm) Appearance100% 30% rate³⁾ Example 1F 1 1000 Polyamide 1F 75:25 750 ⊚ 25 cc 6.8 cc83% (15.6 μeq/g) Example 2F 1 1000 Polyamide 1F 85:15 850 ⊚ 22 cc 6.0 cc90% (15.6 μeq/g) Example 3F 1 1000 Polyamide 1F 45:55 450 ⊚ 24 cc 6.3 cc65% (15.6 μeq/g) Example 4F 2 400 Polyamide 1F 75:25 300 ⊚ 23 cc 6.1 cc81% (15.6 μeq/g) Example 5F 3 2000 Polyamide 1F 75:25 1500 ⊚ 24 cc 6.2cc 79% (15.6 μeq/g) Example 6F 1 1000 Polyamide 2F 75:25 750 ⊚ 17 cc 3.5cc 83% (11.1 μeq/g) Example 7F 1 1000 Polyamide 3F 75:25 750 ⊚ 15 cc 3.1cc 80% (12.2 μeq/g) Example 8F 1 1000 Polyamide 4F 75:25 750 ⊚ to ◯ 10cc 2.8 cc 81% (22.2 μeq/g) Comparative 1 1000 Polyamide 1F 90:10 900 ⊚ 4 cc 0.5 cc 98% Example 1F (15.6 μeq/g) Comparative 1 1000 Polyamide 1F10:90 100 ◯  3 cc 0.5 cc 16% Example 2F (15.6 μeq/g) Comparative 1 1000Polyamide 5F 75:25 750 ⊚  3 cc 0.3 cc 80% Example 3F (38.9 μeq/g)Comparative 1 1000 Polyamide 6F 75:25 750 Δ  4 cc 0.4 cc 81% Example 4F(31.1 μeq/g) ¹⁾(weight of master batch):(weight of polyamide resin)²⁾amount of oxygen absorbed for 7 days since starting the test³⁾measured after stored at 40° C. and a humidity of 100% for 1 month

As apparent from Examples 1F to 8F, the oxygen-absorbing resincompositions obtained by the production process of the present inventionwere resin compositions which showed a good oxygen-absorbing performanceat any of a high humidity and a low humidity and which maintained a filmelasticity after absorbing oxygen.

In contrast with this, the oxygen-absorbing performance wasunsatisfactory in Comparative Example 1F in which a content of thepolyamide A in the resin composition was less than 15% by weight andComparative Example 2F in which it exceeded 60% by weight. Further, thefilm elasticity was deteriorated in Comparative Example 2F.

On the other hand, in Comparative Example 3F in which a mole ratio ofmetaxylylenediamine to adipic acid was increased as compared withExample 7F and Comparative Example 4F in which the solid phasepolymerization time was shortened, an end amino group concentration ofthe polyamide resins obtained exceeded 30 μeq/g, and the goodoxygen-absorbing performances were not obtained. Further, an appearanceof the film was deteriorated as well in Comparative Example 4F.

Example 9F

A two kind, three layer film (thickness: 15 μm/30 μm/15 μm) in which theoxygen-absorbing resin composition obtained in Example 1F was used for acore layer and in which linear low density polyethylene (product name:“ELITE 5220G” manufactured by The Dow Chemical Company, MFR: 3.5 g/10minutes (measured according to JIS K7210), MFR: 8.4 g/10 minutes at 240°C., MFR: 9.1 g/10 minutes at 250° C., hereinafter referred to as LLDPE2) was used for a skin layer was prepared by subjecting one surfacethereof to corona discharge treatment in a width of 800 mm at 100m/minute. Uneven thickness such as humps and the like was not observedon the film roll thus obtained, and it had a good appearance and a HAZEof 20%. The urethane base adhesive for dry laminate (product name:“AD817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.) was used for thecorona discharge-treated surface to obtain an oxygen-absorbingmultilayer film of a silica-deposited PET film (product name: “TechBarrier T” manufactured by Mitsubishi Plastics, Inc., 12)/adhesive(3)/nylon film (product name: “N1202” manufactured by Toyobo Co., Ltd.,15)/adhesive (3)/LLDPE (15)/oxygen-absorbing resin (30)/LLDPE 2 (15).Numbers in parentheses mean the thicknesses (unit: μm) of the respectivelayers.

Next, a three side-sealed bag of 3 cm×5 cm was prepared with a LLDPE 2side turned to an inner face, and the bag was charged with 15 g ofvitamin C powder having a water activity of 0.35 and tightly sealed.Then, it was stored at 23° C. After stored for 2 months, an oxygenconcentration in the bag and an appearance thereof were inspected froman outside of the bag to find that an oxygen concentration in the bagwas 0.1% or less and that an appearance of the vitamin C powder wasmaintained well.

Example 10F

An oxygen-absorbing resin composition was obtained in the same manner asin Example 1F, except that an ethylene-propylene block copolymer(product name: “Novatec PP BC3HF” manufactured by Japan PolypropyleneCorporation, MFR: 8.5 g/10 minutes at 230° C., MFR: 10.8 g/10 minutes at240° C., MFR: 12.1 g/10 minutes at 250° C., hereinafter referred to asPP) was used in place of LLDP 2. Then, a two kind, three layer film(thickness: 20 μm/30 μm/20 μm) was prepared in the same manner as inExample 9F, except that PP was used for a skin layer in place of LLDPE.An appearance of the film thus obtained was good, and a HAZE thereof was80%. The urethane base adhesive for dry laminate (product name:“TM251/CAT-RT88” manufactured by Toyo-Morton, Ltd.) was used for thecorona discharge-treated surface to obtain an oxygen-absorbingmultilayer film of an aluminum-deposited PET film (product name:“GL-ARH-F” manufactured by Toppan Printing Co., Ltd., 12)/adhesive(3)/nylon film (15)/adhesive (3)/PP (20)/oxygen-absorbing resin (30)/PP(20).

Next, a three side-sealed bag of 13 cm×18 cm was prepared with a PP sideturned to an inner face, and the bag was charged with curry containingcarrot, potato, onion and meat and subjected to retort cooking at 127°C. for 30 minutes. It was stored at 23° C. A color tone of the contentafter stored for 6 months was inspected from an outside of the bag tofind that an appearance thereof was maintained well. The bag was opened,and a flavor of the curry was inspected to find that the flavor wasmaintained well.

Comparative Example 7F

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith PP in a weight ratio of 30:70 to obtain an iron powder baseoxygen-absorbing resin composition F. A two kind, three layer film wastried to be prepared in the same manner as in Example 10 by using theabove iron powder base oxygen-absorbing resin composition F for a corelayer, but irregularities of the iron powder were generated on the filmsurface, and the good film was not obtained. Accordingly, the ironpowder base oxygen-absorbing resin composition F was extruded andlaminated as an oxygen-absorbing layer in a thickness of 20 μm on PPhaving a thickness of 40 μm to obtain a laminated film which wassubjected on an oxygen-absorbing layer surface to corona dischargetreatment. Then, an oxygen-absorbing multilayer film ofaluminum-deposited PET film (12)/adhesive (3)/nylon film (15)/adhesive(3)/iron powder base oxygen-absorbing resin composition F (30)/PP (50)was obtained in the same manner as in Example 10F. The oxygen-absorbingmultilayer film thus obtained was used to carry out the same test as inExample 10F to result in finding that the flavor was maintained well butthe content could not be confirmed from an outside of the bag.

As apparent from Examples 9F and 10F, the oxygen-absorbing resincompositions of the present invention had a content visibility, and theywere excellent in an oxygen-absorbing performance at any of a lowhumidity and a high humidity.

Oxygen-Absorbing Multilayer Film and Oxygen-Absorbing MultilayerContainer Example 1G

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1G). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 1G had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 17.5 μeq/g, an end carboxylgroup concentration of 91.6 μeq/g, a number average molecular weight of23500 and MFR of 11.0 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 1G alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1G through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 200 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1GA) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Yumerit 4040F” manufactured by Ube-Maruzen PolyethyleneCo., Ltd., MFR: 4.0 g/10 minutes (measured according to JIS K7210), MFR:7.9 g/10 minutes at 240° C., MFR: 8.7 g/10 minutes at 250° C.,hereinafter referred to as LLDPE 1) as a polyolefin resin in a weightratio of the cobalt stearate-containing polyamide 1GA:LLDPE 1=40:60 toobtain an oxygen-absorbing resin pellet A.

A two kind, two layer film (thickness: oxygen-absorbing resin layer 20μm/oxygen-permeating layer 20 μm) in which the oxygen-absorbing resinpellet A obtained was used for an oxygen-absorbing resin layer and inwhich linear low density polyethylene (product name: “Novatec LL UF641”manufactured by Japan Polyethylene Corporation, MFR: 2.1 g/10 minutes(measured according to JIS K7210), MFR: 4.4 g/10 minutes at 240° C.,MFR: 5.2 g/10 minutes at 250° C., hereinafter referred to as LLDPE 2)was used for an oxygen-permeating layer was subjected on anoxygen-absorbing resin layer surface thereof to corona dischargetreatment in a width of 800 mm at 100 m/minute to prepare a film rollthereof. Uneven thickness such as humps and the like was not observed onthe film roll, and it had a good appearance and a HAZE of 15%. Aurethane base adhesive for dry laminate (product name: “TM-319/CAT-19B”manufactured by Toyo-Morton, Ltd.) was used to laminate a nylon film A(product name: “N1202” manufactured by Toyobo Co., Ltd.), an aluminumfoil and a PET film (product name: “E5102” manufactured by Toyobo Co.,Ltd.) on a corona discharge-treated surface side thereof to obtain anoxygen-absorbing multilayer film comprising an oxygen-absorbingmultilayer film of a PET film (12)/adhesive (3)/aluminum foil(9)/adhesive (3)/nylon film (15)/adhesive (3)/oxygen-absorbing resin(20)/LLDPE 2 (10). Next, a three side-sealed bag of 15×20 cm wasprepared with a LLDPE 2 layer side turned to an inner face, and the bagwas charged with 200 g of a powder seasoning “Dashinomoto” having awater activity of 0.35 and tightly sealed. It was stored at 23° C. Anoxygen concentration in the bag and a flavor of the powder seasoning inthe seventh day and after stored for one month were inspected. Theresults thereof are shown in Table 2G.

Example 2G

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1G, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1GA:LLDPE 1=55:45.Then, a three side-sealed bag was prepared to carry out the same storingtest as in Example 1G. The results thereof are shown in Table 2G.

Example 3G

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1G, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1GA:LLDPE 1=25:75.Then, a three side-sealed bag was prepared to carry out the same storingtest as in Example 1G. The results thereof are shown in Table 2G.

Example 4G

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2G). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 2G had Tg of 65° C., amelting point of 170° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.2 μeq/g, an end carboxylgroup concentration of 80.0 μeq/g, a number average molecular weight of25200 and MFR of 10.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 2G alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.68cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1G so that a cobalt concentration was 200 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 2G)of the polyamide 2G and cobalt stearate was molten and kneaded withLLDPE 1 at 240° C. in a weight ratio of the cobalt stearate-containingpolyamide 2G:LLDPE 1=40:60 to obtain an oxygen-absorbing resin pellet.Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1G, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1G. The results thereofare shown in Table 2G.

Example 5G

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 3G). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 3G had Tg of 78° C., amelting point of 194° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.5 μeq/g, an end carboxylgroup concentration of 81.2 μeq/g, a number average molecular weight of24500 and MFR of 10.5 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 3G alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.21cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1G so that a cobalt concentration was 200 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 3G)of the polyamide 3G and cobalt stearate was molten and kneaded withLLDPE 1 at 240° C. in a weight ratio of the cobalt stearate-containingpolyamide 3G:LLDPE 1=40:60 to obtain an oxygen-absorbing resin pellet.Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1G, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1G. The results thereofare shown in Table 2G.

Example 6G

Metaxylylenediamine:adipic acid were used in a mole ratio of 0.994:1 andsubjected to melt polymerization and solid phase polymerization on thesynthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide4G). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 4hours. The above polyamide 4G had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 19.8 μeq/g, an end carboxyl group concentration of 67.0μeq/g and a number average molecular weight of 23000. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 14.4 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 4G alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4G, and the mixture wasmolten and kneaded with LLDPE 1 in the same manners as in Example 1G,except that the temperature in melting and kneading was changed to 250°C. Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1G, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1G. The results thereofare shown in Table 2G.

Example 7G

Metaxylylenediamine and paraxylylenediamine were mixed in 8:2, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 270° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 5G). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 270° C. and thereaction time to 30 minutes. The above polyamide 5G had Tg of 85° C., amelting point of 255° C., a semi-crystallization time of 24 seconds, anend amino group concentration of 23.5 μeq/g, an end carboxyl groupconcentration of 63.2 μeq/g and a number average molecular weight of18900. MFR could not be measured at 260° C. since it was close to themelting point, and MFR at 270° C. was measured to find that MFR at 270°C. was 35.7 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 5G alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 5G, and the mixture wasmolten and kneaded with LLDPE 1 in the same manners as in Example 1G,except that the temperature in melting and kneading was changed to 270°C. Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1G, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1G. The results thereofare shown in Table 2G.

Example 8G

Metaxylylenediamine:adipic acid:isophthalic acid were used in a moleratio of 0.991:0.9:0.1 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 6G). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 205°C. and the polymerization time to 4 hours. The above polyamide 6G had Tgof 94° C., a melting point of 228° C., a semi-crystallization time of300 seconds, an end amino group concentration of 14.8 μeq/g, an endcarboxyl group concentration of 67.2 μeq/g and a number averagemolecular weight of 23000. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 15.4 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 6G alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.08cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6G, and the mixture wasmolten and kneaded with LLDPE 1 in the same manners as in Example 1G,except that the temperature in melting and kneading was changed to 250°C. Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1G, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1G. The results thereofare shown in Table 2G.

Comparative Example 1G

A film was produced in the same manner as in Example 1G, except that aweight ratio in melting and kneading was changed to the cobaltstearate-containing polyamide 1GA:LLDPE 1=70:30. Then, a threeside-sealed bag was prepared to carry out the same storing test as inExample 1G. The results thereof are shown in Table 2G.

Comparative Example 2G

A film was produced in the same manner as in Example 1G, except that themixture was not molten and not kneaded with LLDPE 1 and that the filmwas prepared only from the cobalt stearate-containing polyamide 1GA.Then, a three side-sealed bag was prepared to carry out the same storingtest as in Example 1G. The results thereof are shown in Table 2G.

Comparative Example 3G

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide resin 7G) was synthesized in the same manner as inExample 6G, except that metaxylylenediamine:adipic acid were used in amole ratio of 1:1. The above polyamide 7G had Tg of 84° C., a meltingpoint of 237° C., a semi-crystallization time of 25 seconds, an endamino group concentration of 42.4 μeq/g, an end carboxyl groupconcentration of 43.5 μeq/g and a number average molecular weight of23300. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 14.1 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 7G alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 7G, and the mixture wasmolten and kneaded with LLDPE 1 in the same manners as in Example 6G toproduce a film in the same manner as in Example 1G. Then, a threeside-sealed bag was prepared to carry out the same storing test as inExample 1G. The results thereof are shown in Table 2G.

Comparative Example 4G

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide resin 8G) was synthesized in the same manner as inExample 6G, except that metaxylylenediamine:adipic acid were used in amole ratio of 0.994:1 and that the polymerization time in the solidphase polymerization was changed to 2 hours. The above polyamide 8G hadTg of 84° C., a melting point of 237° C., a semi-crystallization time of25 seconds, an end amino group concentration of 31.4 μeq/g, an endcarboxyl group concentration of 76.6 μeq/g and a number averagemolecular weight of 18500. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 31.2 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 8G alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.09cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 8G, and the mixture wasmolten and kneaded with LLDPE 1 in the same manners as in Example 6G toproduce a film in the same manner as in Example 1G. Then, a threeside-sealed bag was prepared to carry out the same storing test as inExample 1G. The results thereof are shown in Table 2G.

The respective details of the polyamides 1G to 8G obtained above areshown in Table 1G, and the results of the respective examples andcomparative examples are shown in Table 2G.

TABLE 1G Oxygen End amino permeability group Solid MFR Coefficient⁴⁾concentration phase End (g/10 (cc · mm/(m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ masking³⁾ minutes) day · atm))Polyamide 1G 17.5 MXDA Sebacic acid (0.4) ∘ x 11.0 0.34 (0.992) Adipicacid (0.6) (4 hours) (240° C.) Polyamide 2G 19.2 MXDA Sebacic acid (0.7)∘ x 10.1 0.68 (0.992) Adipic acid (0.3) (4 hours) (240° C.) Polyamide 3G19.5 MXDA Sebacic acid (0.3) ∘ x 10.5 0.21 (0.992) Adipic acid (0.7) (4hours) (240° C.) Polyamide 4G 19.8 MXDA Adipic acid (1.0) ∘ x 14.4 0.09(0.994) (4 hours) (250° C.) Polyamide 5G 23.5 MXDA Adipic acid (1.0) x ∘35.7 0.13 (0.8) (270° C.) PXDA (0.2) Polyamide 6G 14.8 MXDA Adipic acid(0.9) ∘ x 15.4 0.08 (0.991) Isophthalic acid (0.1) (4 hours) (250° C.)Polyamide 7G 42.4 MXDA Adipic acid (1.0) ∘ x 14.1 0.09 (1.0) (4 hours)(250° C.) Polyamide 8G 31.4 MXDA Adipic acid (1.0) ∘ x 31.2 0.09 (0.994)(2 hours) (250° C.) MXDA: metaxylylenediamine, PXDA: paraxylylenediamine¹⁾Numerical value in parentheses shows a mole ratio of each component.²⁾∘: the solid phase polymerization was carried out. The polymerizationtime is shown in parentheses. x: the solid phase polymerization was notcarried out. ³⁾∘: the end amino group was masked. x: the end amino groupwas not masked. ⁴⁾A non-stretched film was prepared from the polyamidealone, and an oxygen permeability coefficient thereof was measured at23° C. and 60% RH.

TABLE 2G Composition Polyamide Appearance Oxygen (end amino Melting ofconcentration group kneading film After After Flavor after concentrationratio¹⁾ roll 7 days 1 month 1 month Example 1G Polyamide 1G 40:60 Good0.4% 0.1% Good (17.5 μeq/g) or less Example 2G Polyamide 1G 55:45 Good3.3% 0.5% Almost (17.5 μeq/g) good Example 3G Polyamide 1G 25:75 Good2.3% 0.1% Good (17.5 μeq/g) or less Example 4G Polyamide 2G 40:60 Good0.9% 0.1% Good (19.2 μeq/g) or less Example 5G Polyamide 3G 40:60 Good0.9% 0.1% Good (19.5 μeq/g) or less Example 6G Polyamide 4G 40:60 Good4.7% 0.9% Almost (19.8 μeq/g) good Example 7G Polyamide 5G 40:60Slightly 5.2% 1.0% Almost (23.5 μeq/g) inferior good Example 8GPolyamide 6G 35:65 Good 3.1% 0.3% Almost (14.8 μeq/g) good ComparativePolyamide 1G 70:30 Slightly 8.9% 3.5% lowered Example 1G (17.5 μeq/g)inferior Comparative Polyamide 1G 100:0  Good 16.0% 10.3%  loweredExample 2G (17.5 μeq/g) Comparative Polyamide 7G 40:60 Good 9.5% 3.8%lowered Example 3G (42.4 μeq/g) Comparative Polyamide 8G 40:60 Slightly8.5% 3.2% lowered Example 4G (31.4 μeq/g) inferior ¹⁾(total weight oftransition metal catalyst and polyamide resin):weight of polyolefinresin

Example 9G

A two kind, three layer film (thickness: 10 μm/20 μm/10 μm) in which theoxygen-absorbing resin pellet A was used for a core layer and in whichLLDPE 2 was used for a skin layer was subjected on one surface thereofto corona discharge treatment in a width of 800 mm at 110 m/minute toprepare a film roll thereof.

Obtained by extrusion lamination using linear low density polyethylene(product name: “Kernel KC580S” manufactured by Japan PolyethyleneCorporation, hereinafter referred to as LLDPE 3) was an oxygen-absorbingmultilayer film of an aluminum-deposited PET film (product name:“GL-ARH-F” manufactured by Toppan Printing Co., Ltd., 12)/adhesive forlaminate (3)/nylon film A (15)/urethane base anchor coating agent(product name: “A3210/A3075” manufactured by Mitsui Chemicals, Inc.,0.5)/LLDPE 3 (15)/LLDPE 2 (10)/oxygen-absorbing resin (20)/LLDPE 2 (10).The above film was processed into a self-supported bag (130×175×35 mm)comprising two side face films and one bottom face film with a LLDPE 2layer side turned to an inner face, and a processability of the bag wasgood. The bag was charged with cucumbers together with a solutioncontaining acetic acid in a total amount of 200 g by high speedautomatic charging at a rate of 40 bags/minute to find that an openingproperty of the bag was good and that heat sealing thereof was carriedout without having any problems. The 100 bags which were charged andtightly sealed were subjected to boiling treatment at 90° C. for 30minutes and then stored at 23° C. to inspect a flavor of the cucumbersand an appearance of the self-supported bags after one month. Thecucumbers could be visually confirmed from an outside of the bags, and aflavor and a color tone of the cucumbers were maintained well. Anappearance of the bags was not abnormal.

Comparative Example 5G

An oxygen-absorbing resin pellet was produced in the same manner as inExample 1G, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1GA:LLDPE 1=80:20.Then, the above pellet was used to prepare an oxygen-absorbingmultilayer film in the same manner as in Example 9F, and the film wasprocessed into a self-supported bag. The bags were charged withcucumbers together with a solution containing acetic acid in a totalamount of 200 g in the same manner as in Example 9G to find that asealing strength of the above bag was weak and that in particular, theoxygen-permeating layer was peeled off from the oxygen-absorbing resinlayer. The charged bags were subjected to boiling treatment at 90° C.for 30 minutes, and the 62 bags were broken. The remaining bags weresubjected to the same storing test as in Example 9G to find that aflavor and a color tone of the cucumbers were lowered. An appearance ofthe bags was not abnormal.

Comparative Example 6G

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith LLDPE in a weight ratio of 30:70 to obtain an iron powder baseoxygen-absorbing resin composition AG. A two kind, three layer film wastried to be prepared in the same manner as in Example 9G by using theiron powder base oxygen-absorbing resin composition AG for a core layer,but irregularities of the iron powder were generated on the filmsurface, and the film was not obtained. Accordingly, the iron powderbase oxygen-absorbing resin composition Ag was extruded and laminated asan oxygen-absorbing layer in a thickness of 20 μm on a linear lowdensity polyethylene film (product name: “Tohcello T.U.X HC”manufactured by Mitsui Chemicals Tohcello, Inc., hereinafter referred toas LLDPE 4) having a thickness of 40 μm to obtain a laminated film whichwas subjected on an oxygen-absorbing layer surface to corona dischargetreatment.

The above laminated film was laminated in the same manner as in Example9G to prepare an iron base oxygen-absorbing multilayer film of analuminum-deposited PET film (12)/adhesive for laminate (3)/nylon film(15)/urethane base anchor coating agent (0.5)/LLDPE 3 (15)/iron baseoxygen-absorbing resin composition AG (20)/LLDPE 4 (40). It wasprocessed into a self-supported bag in the same manner as in Example 9G.

The bags were tried to be charged with cucumbers together with asolution containing acetic acid in a total amount of 200 g in the samemanner as in Example 9G, but an opening property of the bags wasinferior, and the content was spilled out in several bags and could notbe charged therein. Further, the storing test was carried out after theboiling treatment in the same manner as in Example 9G, but the cucumberscould not be visually confirmed from an outside of the bags, so that thebags were opened. A flavor and a color tone of the cucumbers weremaintained well, but irregularities were generated on an appearance ofthe bags, and delamination was brought about on a part thereof.

Example 10G

An oxygen-absorbing resin pellet B was obtained in the same manner as inExample 1G, except that an ethylene-propylene random copolymer (productname: “Novatec PP FW4BT” manufactured by Japan PolypropyleneCorporation, MFR: 6.5 g/10 minutes at 230° C., MFR: 8.3 g/10 minutes at240° C., hereinafter referred to as PP 1) was used in place of LLDPE 1.An oxygen-absorbing resin layer 30 μm comprising the oxygen-absorbingresin pellet B and an oxygen-permeating layer 30 μm comprising an olefinbase polymer alloy (product name: “VMX X150F” manufactured by MitsubishiChemical Corporation, MFR: 3.5 g/10 minutes at 190° C., MFR: 7.9 g/10minutes at 240° C.) were laminated to prepare a two kind, two layerfilm. Subsequently, an ethylene-vinyl alcohol copolymer film (productname: “Eval EF-XL” manufactured by Kuraray Co., Ltd.) 15 μm and a nylonfilm B (product name: “N1102” manufactured by Toyobo Co., Ltd) 15 μmlaminated by using an adhesive for laminate to obtain anoxygen-absorbing multilayer film of a nylon film B (15)/adhesive forlaminate (3)/ethylene vinyl alcohol copolymer film (15)/adhesive forlaminate (3)/oxygen-absorbing resin (30)/olefin base polymer alloy (30).An appearance of the film was good.

Next, an ethylene-propylene random copolymer (product name: “Novatec PPEG7F” manufactured by Japan Polyethylene Corporation, MFR: 1.3 g/10minutes (measured according to JIS K7210), MFR: 8.2 g/10 minutes at 240°C., MFR: 9.8 g/10 minutes at 250° C., hereinafter referred to as PP 2)was used to prepare a sheet of PP 2 (400)/maleic anhydride-modifiedpolypropylene (product name: “Admer QF500” manufactured by MitsuiChemicals, Inc. 15)/ethylene-vinyl alcohol copolymer A (product name:“Eval L104B” manufactured by Kuraray Co., Ltd., 40)/maleicanhydride-modified polypropylene (product name: same as above, 15)/PP2(40), and this was molded into a cup of 70 cc at a drawing ratio of 2.5.The above cup was fully charged with an orange jelly and tightly sealedby using the prepared oxygen-absorbing multilayer film as a covermaterial with a nylon film B layer side turned to an outer face. A colortone of the content could be visually confirmed through the covermaterial. The tightly sealed container was subjected to heatingtreatment at 85° C. for 30 minutes and then stored at 23° C. for onemonth. After one month, the container was opened to find that an openingproperty thereof was good without being turned into a double cap andthat a flavor and a color tone of the content were maintained well.

Example 11G

An oxygen-absorbing multilayer film and a cup of 70 cc which wereobtained in the same manner as in Example 10G were used and subjectedrespectively to hydrogen peroxide sterilization treatment by dipping.Abnormality was not brought about on the oxygen-absorbing multilayerfilm in the sterilization. The cup was charged in a hot state withstrawberry jam kept at 80° C. and tightly sealed by using theoxygen-absorbing multilayer film as a cover material with a nylon film Blayer side turned to an outside. The tightly sealed container was storedat 23° C. for one month. After one month, the content was visuallyconfirmed through the cover material to find that a color tone thereofwas maintained well. The cover material was opened to find that anopening property thereof was good without being turned into a double capand that a flavor of the content was maintained well.

Comparative Example 7G

An iron base oxygen-absorbing multilayer film having an iron baseoxygen-absorbing resin layer obtained in the same manner as inComparative Example 7G was subjected to hydrogen peroxide sterilizationtreatment by the same method as in Example 11G to find that air bubbleswere generated in hydrogen peroxide and that the sterilization could notbe continued.

As apparent from Examples 1G to 11G, the oxygen-absorbing multilayerfilms of the present invention are turned into storing containers whichare excellent in an oxygen-absorbing performance, a processability and astrength and can be subjected to heating treatment and which can beapplied to foods incapable of being stored in oxygen-absorbingmultilayer films prepared by using an iron base oxygen-absorbing agentand can be subjected to hydrogen peroxide sterilization. Further, theyhave an inside visibility to make it possible to confirm a color toneand the like in the content and can be applied to a cover material ofcontainers.

The present invention relates to the oxygen-absorbing multilayer filmswhich are excellent in an oxygen-absorbing performance at a low humidityand a high humidity and maintain a resin strength after stored and whichare excellent in a processability and can be applied to variouscontainers and uses by preparing the multilayer films having anoxygen-absorbing resin layer prepared by blending the specific polyamideresin and the transition metal catalyst with the polyolefin resin in aspecific proportion.

Example 12G

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1G through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1 GB) of the polyamide 1G and cobaltstearate was molten and kneaded with PP 2 as the polyolefin resin at240° C. in a weight ratio of the cobalt stearate-containing polyamide 1GB:PP 2=40:60 by means of the biaxial extruding equipment to obtain anoxygen-absorbing resin pellet C.

Then, a four kind, six layer multilayer sheet-molding apparatuscomprising first to fourth extruding equipments, a feed block, a T die,a cooling roll and a sheet receiving equipment was used to extrudecomponents from the respective extruding equipments to obtain anoxygen-absorbing multilayer sheet, wherein extruded were PP2 from thefirst extruding equipment, the oxygen-absorbing resin pellet C describedabove from the second extruding equipment, an ethylene-vinyl alcoholcopolymer B (product name: “Eval L171B” manufactured by Kuraray Co.,Ltd.) from the third extruding equipment and a polypropylene baseadhesive resin (product name: Modec AP P604V manufactured by MitsubishiChemical Corporation) from the fourth extruding equipment. Theconstitution of the above multilayer sheet is PP 2 (80)/oxygen-absorbingresin (100)/adhesive layer (15)/ethylene-vinyl alcohol copolymer B(30)/adhesive layer (15)/PP 2 (250) from the inner layer. The multilayersheet prepared by co-extrusion was a multilayer sheet which was freefrom thickness unevenness and the like and had a good appearance.

Next, the multilayer sheet thus obtained was subjected to thermoformingprocessing into a tray-like container (inner volume: 350 cc, surfacearea: 200 cm²) with the inner layer turned to an inside by means of avacuum molding machine. The oxygen-absorbing multilayer containerobtained was free from thickness unevenness and had a good appearance.The above container was sterilized by a UV ray and charged with 200 g ofsterile rice immediately after cooked, and oxygen in an inside of thecontainer was substituted with nitrogen to reduce an oxygenconcentration to 0.5%. Then, a gas-barriering film (PET film(12)/adhesive for laminate (3)/MXD6 base multilayer co-extruded nylonfilm (15)/adhesive for laminate (3)/non-stretched polypropylene film(60)) prepared by dry-laminating a PET film, a MXD6 base multilayerco-extruded nylon film (product name: “Supernyl SP-R” manufactured byMitsubishi Plastics, Inc.) and a non-stretched polypropylene film(product name: “Aroma UT21” manufactured by Okamoto Industries,Incorporated.) by an adhesive for laminate was used as a top film totightly seal the container described above after sterilized by a UV rayas was the case with the container, and it was stored on the conditionsof 23° C. and 50% RH. An oxygen concentration in the container after 3months since starting storage was measured, and then the container wasopened to confirm a flavor of the cooked rice and a strength of theoxygen-absorbing container. The results thereof are shown in Table 3G.

Example 13G

An oxygen-absorbing multilayer sheet was prepared in the same manner asin Example 12G, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1G:PP 2=60:40. Then,an oxygen-absorbing multilayer container was prepared to carry out thesame storing test as in Example 12G. The results thereof are shown inTable 3G.

Example 14G

An oxygen-absorbing multilayer sheet was prepared in the same manner asin Example 12G, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1 GB:PP 2=25:75.Then, an oxygen-absorbing multilayer container was prepared to carry outthe same storing test as in Example 12G. The results thereof are shownin Table 3G.

Example 15G

An oxygen-absorbing multilayer sheet was prepared in the same manner asin Example 12G, except that the polyamide 2G was used in place of thepolyamide 1G. Then, an oxygen-absorbing multilayer container wasprepared to carry out the same storing test as in Example 12G. Theresults thereof are shown in Table 3G.

Comparative Example 8G

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith PP 2 in a weight ratio of 30:70 to obtain an iron baseoxygen-absorbing resin composition BG. Subsequently, an oxygen-absorbingmultilayer sheet was prepared in the same manner as in Example 12G,except that the iron base oxygen-absorbing resin composition BG was usedfor an oxygen-absorbing resin layer. The constitution of the abovemultilayer sheet was PP 2 (80)/oxygen-absorbing resin composition BG(100)/adhesive layer (15)/ethylene-vinyl alcohol copolymer B(30)/adhesive layer (15)/PP 2 (250) from the inner layer. The iron basemultilayer sheet obtained was tried to be thermoformed to prepare atray-like container, but drawdown was brought about, and therefore theprocessing was difficult. Further, the container prepared was opaquesince the iron powder was used, and an appearance thereof was inferiordue to irregularities originating in the iron powder. However, thecontainer passing an appearance was obtained, and therefore the samestoring test as in Example 12G was carried out. The results thereof areshown in Table 3G.

Comparative Example 9G

An oxygen-absorbing multilayer sheet was prepared in the same manner asin Example 12G, except that the mixture was not molten and kneaded withPP 2 and that an oxygen-absorbing resin pellet comprising only thecobalt stearate-containing polyamide 1G was prepared and used for anoxygen-absorbing resin layer. Then, an oxygen-absorbing multilayercontainer was prepared to carry out the same storing test as in Example12G. The results thereof are shown in Table 3G.

TABLE 3G Oxygen-absorbing resin pellet Polyamide G (end amino MeltingOxygen group kneading Oxygen-absorbing container concentration Flavor ofconcentration) ratio¹⁾ Moldability Transparency Strength in containercooked rice Example 12G Polyamide 1G 40:60 Good Good Good 0.1% Good(17.5 μeq/g) or less Example 13G Polyamide 1G 60:40 Slightly SlightlyAlmost 0.1% Good (17.5 μeq/g) inferior inferior good or less Example 14GPolyamide 1G 25:75 Good Good Good 0.1% Good (17.5 μeq/g) or less Example15G Polyamide 2G 40:60 Good Good Good 0.1% Good (19.2 μeq/g) or lessComparative —²⁾ Inferior None Good 0.1% Good Example 8G or lessComparative Polyamide 1G 100:0  Slightly Good Reduced 0.9% ReducedExample 9G (17.5 μeq/g) inferior ¹⁾(total weight of transition metalcatalyst and polyamide resin):weight of polyolefin resin ²⁾The iron baseoxygen-absorbing resin composition BG was used as the oxygen-absorbingresin composition.

As apparent from Examples 12G to 15G, the oxygen-absorbing multilayercontainers of the present invention show a good moldability and a goodoxygen-absorbing performance and are transparent, and a strength of thecontainers can be maintained even after absorbing oxygen.

Example 16G

A two kind, three layer film (thickness: 10 μm/10 μm/10 μm) in which theoxygen-absorbing resin pellet B was used for a core layer and in whichPP 1 was used for a skin layer was prepared by subjecting one surfacethereof to corona discharge treatment in a width of 800 mm at 100m/minute. The oxygen-absorbing multilayer container obtained had a goodappearance.

The above oxygen-absorbing multilayer container and a polypropylenesheet of 200 μm (product name: “NS3451” manufactured by SumitomoBakelite Co., Ltd.) were dry-laminated by using a gas-barrieringadhesive (product name: “Maxive” manufactured by Mitsubishi Gas ChemicalCompany, Inc.) to prepare an oxygen-absorbing multilayer sheet of PP 1(10)/oxygen-absorbing resin (10)/PP 1 (10)/gas-barriering adhesive(3)/polypropylene sheet (200) from an inner layer. Then, the aboveoxygen-absorbing multilayer sheet was vacuum-molded with an inner layerturned to an inside to mold a pocket (diameter: 12 mm, depth: 5 mm) ofpress•through•pack. Further, a urethane base anchor coating agent(product name: “A3210” manufactured by Mitsui Chemicals Polyurethane,Inc.) was coated on an aluminum foil of 25 μm, and polypropylene(product name: “F329RA” manufactured by Prime Polymer Co., Ltd.) wasextrusion-coated thereon as a heat sealing material in a thickness of 25μm to obtain an aluminum foil-coated film of an aluminum foil(25)/anchor coating agent (1)/polypropylene (25). The pocket was chargedwith 2 g of vitamin C tablets having a water activity of 0.35 andtightly sealed by heat-sealing it with the aluminum foil-coated film,and then it was stored at 23° C. After stored for one month, an oxygenconcentration in the bag and an appearance thereof were inspected tofind that an oxygen concentration in the pocket was 0.1% or less andthat an appearance of the vitamin C tablets was maintained well.

Example 17G

An oxygen-absorbing multilayer sheet was prepared in the same manner asin Example 12G. The constitution of the above multilayer sheet was PP 2(90)/oxygen-absorbing resin (80)/adhesive layer (15)/ethylene-vinylalcohol copolymer B (30)/adhesive layer (15)/PP 2 (250) from the innerlayer. Then, the above multilayer sheet was thermoformed into a cup-likecontainer (inner volume: 100 cc, surface area: 96 cm²) with an innerlayer turned to an inside by means of a vacuum molding machine. Mistyhydrogen peroxide was sprayed onto the above container, and then it wasdried by hot air and sterilized. Then, the container was charged withorange jam and tightly sealed by using for a top film, a gas-barrieringfilm obtained in the same manner as in Example 12G and sterilizedsimilarly by hydrogen peroxide, and then it was stored at 23° C. Afterstored for one month, an oxygen concentration in the container was 0.1%or less, and a flavor of the orange jam was maintained.

Comparative Example 10G

An iron base oxygen-absorbing multilayer sheet was prepared in the samemanner as in Comparative Example 8G. The constitution of the abovemultilayer sheet was PP 2 (90)/iron base oxygen-absorbing resincomposition BG (80)/adhesive layer (15)/ethylene-vinyl alcohol copolymerB (30)/adhesive layer (15)/PP 2 (250) from the inner layer. Then, theabove multilayer sheet was tried to be thermoformed to prepare the samecup-like container as in Example 17G, but drawdown was brought about,and the processing was difficult. However, the container passing anappearance was obtained, and therefore misty hydrogen peroxide wassprayed onto the container to find that the iron powder exposed at anend face of the container was reacted with hydrogen peroxide to makesterilization difficult. After dried by hot air, the iron powder at theend face rusted.

The present invention relates to the oxygen-absorbing multilayercontainer prepared by thermoforming the oxygen-absorbing multilayer filmwhich is excellent in an oxygen-absorbing performance at a low humidityand a high humidity and maintains a resin strength after stored andwhich is excellent in a processability and can be applied to variouscontainers and uses by blending the specific polyamide resin and thetransition metal catalyst with the polyolefin resin in a specificproportion.

Example 1H

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1H). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 1H had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 17.5 μeq/g, an end carboxylgroup concentration of 91.6 μeq/g, a number average molecular weight of23500 and MFR of 11.0 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 1H alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1H through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1H) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Yumerit 4040F” manufactured by Ube-Maruzen PolyethyleneCo., Ltd., MFR: 4.0 g/10 minutes (measured according to JIS K7210), MFR:7.9 g/10 minutes at 240° C., MFR: 8.7 g/10 minutes at 250° C.,hereinafter referred to as LLDPE 1) as a polyolefin resin and maleicanhydride-modified polyethylene (product name: “Modec AP M545”manufactured by Mitsubishi Gas Chemical Company, Inc., MFR: 6.0 g/10minutes (measured according to JIS K7210), MFR: 14.4 g/10 minutes at240° C., MFR: 16.1 g/10 minutes at 250° C., hereinafter referred to asMAPE) as a maleic anhydride-modified polyethylene resin in a weightratio of the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=40:50:10 to obtain an oxygen-absorbing resin pellet A.

A two kind, three layer film (thickness: intermediate LLDPE 2 layer 10μm/oxygen-absorbing resin layer 20 μm/sealant LLDPE 2 layer 10 μm) inwhich the oxygen-absorbing resin pellet A obtained was used for anoxygen-absorbing resin layer and in which linear low densitypolyethylene (product name: “ELITE 5220G” manufactured by The DowChemical Company, MFR: 3.5 g/10 minutes (measured according to JISK7210), MFR: 8.4 g/10 minutes at 240° C., MFR: 9.1 g/10 minutes at 250°C., hereinafter referred to as LLDPE 2) was used for a sealant layer andan intermediate layer was subjected on an intermediate layer surfacethereof to corona discharge treatment in a width of 760 mm at 60m/minute to prepare a film roll thereof. Uneven thickness such as humpsand the like was not observed on the film roll, and it had a goodappearance and a HAZE of 19%. A urethane base adhesive for dry laminate(product: “AD-817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.) wasused to laminate a nylon film A (product name: “N1202” manufactured byToyobo Co., Ltd.) and an aluminum-deposited PET film (product name:“GL-ARH-F” manufactured by Toppan Printing Co., Ltd.) on acorona-treated surface side to obtain an oxygen-absorbing multilayerfilm comprising an oxygen-absorbing multilayer film of analuminum-deposited PET film (12)/adhesive (3)/nylon film A (15)/adhesive(3)/LLDPE 2 (10)/oxygen-absorbing resin (20)/LLDPE 2 (10). Numbers inparentheses mean a thickness (unit: μm) of the respective layers. Next,a three side-sealed bag of 11 cm×17 cm was prepared with a sealant layerside turned to an inner face, and the bag was charged with 80 g oforange and 80 g of a fruit syrup liquid. Then, it was tightly sealed sothat a head space air amount was 5 cc and subjected to boiling treatmentat 90° C. for 30 minutes to measure the sealing strength after theboiling treatment. Then, the remaining sample was stored at 40° C. and100% RH. A concentration of oxygen in an inside of the bag in theseventh day and a color tone of the orange after stored for one monthwere inspected from an outside of the bag, and a flavor thereof wasinspected by opening the bag. The results thereof are shown in Table 2H.

Comparative Example 2H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=40:55:5. Then, a three side-sealed bag was prepared to carry outthe same storing test as in Example 1H. The results thereof are shown inTable 2H.

Comparative Example 3H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=40:45:15. Then, a three side-sealed bag was prepared to carry outthe same storing test as in Example 1H. The results thereof are shown inTable 2H.

Comparative Example 4H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=40:35:25. Then, a three side-sealed bag was prepared to carry outthe same storing test as in Example 1H. The results thereof are shown inTable 2H.

Example 5H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=55:35:10. Then, a three side-sealed bag was prepared to carry outthe same storing test as in Example 1H. The results thereof are shown inTable 2H.

Example 6H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=25:70:5. Then, a three side-sealed bag was prepared to carry outthe same storing test as in Example 1H. The results thereof are shown inTable 2H.

Example 7H

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2H). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 2H had Tg of 65° C., amelting point of 170° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.2 μeq/g, an end carboxylgroup concentration of 80.0 μeq/g, a number average molecular weight of25200 and MFR of 10.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 2H alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.68cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1H so that a cobalt concentration was 400 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 2H)of the polyamide 2H and cobalt stearate was molten and kneaded withLLDPE 1 and MAPE at 240° C. in a weight ratio of the cobaltstearate-containing polyamide 2H:LLDPE 1: MAPE=40:50:10 to obtain anoxygen-absorbing resin pellet. Further, an oxygen-absorbing multilayerfilm was obtained in the same manner as in Example 1H, and then a threeside-sealed bag was prepared to carry out the same storing test as inExample 1H. The results thereof are shown in Table 2H.

Example 8H

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 3H). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 3H had Tg of 78° C., amelting point of 194° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.5 μeq/g, an end carboxylgroup concentration of 81.2 μeq/g, a number average molecular weight of24500 and MFR of 10.5 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 3H alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.21cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1H so that a cobalt concentration was 400 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 3H)of the polyamide 3H and cobalt stearate was molten and kneaded withLLDPE 1 and MAPE at 240° C. in a weight ratio of the cobaltstearate-containing polyamide 3H:LLDPE 1: MAPE=40:50:10 to obtain anoxygen-absorbing resin pellet. Further, an oxygen-absorbing multilayerfilm was obtained in the same manner as in Example 1H, and then a threeside-sealed bag was prepared to carry out the same storing test as inExample 1H. The results thereof are shown in Table 2H.

Example 9H

Metaxylylenediamine:adipic acid were used in a mole ratio of 0.994:1 andsubjected to melt polymerization and solid phase polymerization on thesynthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide4H). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 4hours. The above polyamide 4H had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 19.8 μeq/g, an end carboxyl group concentration of 67.0μeq/g and a number average molecular weight of 23000. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 14.4 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 4H alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4H, and the mixture wasmolten and kneaded with LLDPE 1 and MAPE in the same manners as inExample 1H, except that the temperature in melting and kneading waschanged to 250° C. Further, an oxygen-absorbing multilayer film wasobtained in the same manner as in Example 1H, and then a threeside-sealed bag was prepared to carry out the same storing test as inExample 1H. The results thereof are shown in Table 2H.

Example 10H

Metaxylylenediamine and paraxylylenediamine were mixed in 8:2, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 270° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 5H). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 270° C. and thereaction time to 30 minutes. The above polyamide 5H had Tg of 85° C., amelting point of 255° C., a semi-crystallization time of 24 seconds, anend amino group concentration of 23.5 μeq/g, an end carboxyl groupconcentration of 63.2 μeq/g and a number average molecular weight of18900. MFR could not be measured at 260° C. since it was close to themelting point, and MFR at 270° C. was measured to find that MFR at 270°C. was 35.7 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 5H alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 5H, and the mixture wasmolten and kneaded with LLDPE 1 and MAPE in the same manners as inExample 1H, except that the temperature in melting and kneading waschanged to 270° C. Further, an oxygen-absorbing multilayer film wasobtained in the same manner as in Example 1H, and then a threeside-sealed bag was prepared to carry out the same storing test as inExample 1H. The results thereof are shown in Table 2H.

Example 11H

Metaxylylenediamine:sadipic acid:isophthalic acid were used in a moleratio of 0.991:0.9:0.1 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 6H). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 205°C. and the polymerization time to 4 hours. The above polyamide 6H had Tgof 94° C., a melting point of 228° C., a semi-crystallization time of300 seconds, an end amino group concentration of 14.8 μeq/g, an endcarboxyl group concentration of 67.2 μeq/g and a number averagemolecular weight of 23000. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 15.4 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 6H alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.08cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6H, and the mixture wasmolten and kneaded with LLDPE 1 and MAPE in the same manners as inExample 1H, except that the temperature in melting and kneading waschanged to 250° C. Further, an oxygen-absorbing multilayer film wasobtained in the same manner as in Example 1H, and then a threeside-sealed bag was prepared to carry out the same storing test as inExample 1H. The results thereof are shown in Table 2H.

Comparative Example 1H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=10:85:5. Then, a three side-sealed bag was prepared to carry outthe same storing test as in Example 1H. The results thereof are shown inTable 2H.

Comparative Example 2H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:LLDPE 1:MAPE=70:20:10. Then, a three side-sealed bag was prepared to carry outthe same storing test as in Example 1H. The results thereof are shown inTable 2H.

Comparative Example 3H

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 7H) was synthesized in the same manner as in Example 9,except that metaxylylenediamine and adipic acid were used in a moleratio of 1:1. The above polyamide 7H had Tg of 84° C., a melting pointof 237° C., a semi-crystallization time of 25 seconds, an end aminogroup concentration of 42.4 μeq/g, an end carboxyl group concentrationof 43.5 μeq/g and a number average molecular weight of 23300. MFR couldnot be measured at 240° C. since it was close to the melting point, andMFR at 250° C. was measured to find that MFR at 250° C. was 14.1 g/10minutes. A non-stretched film was prepared from the resulting polyamide7G alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 7H, and the mixture wasmolten and kneaded with LLDPE 1 and MAPE in the same manners as inExample 9H to produce a film in the same manner as in Example 1H. Then,a three side-sealed bag was prepared to carry out the same storing testas in Example 1H. The results thereof are shown in Table 2H.

Comparative Example 4H

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 8H) was synthesized in the same manner as in Example9H, except that metaxylylenediamine:adipic acid were used in a moleratio of 0.994:1 and that the polymerization time in the solid phasepolymerization was changed to 2 hours. The above polyamide 8H had Tg of84° C., a melting point of 237° C., a semi-crystallization time of 25seconds, an end amino group concentration of 31.4 μeq/g, an end carboxylgroup concentration of 76.6 μeq/g and a number average molecular weightof 18500. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 31.2 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 8H alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 8H, and the mixture wasmolten and kneaded with LLDPE 1 and MAPE in the same manners as inExample 9H to produce a film in the same manner as in Example 1H. Then,a three side-sealed bag was prepared to carry out the same storing testas in Example 1H. The results thereof are shown in Table 2H.

The respective details of the polyamides 1H to 8H obtained above areshown in Table 1H, and the results of the respective examples andcomparative examples are shown in Table 2H.

TABLE 1H Oxygen End amino permeability group Solid MFR Coefficient⁴⁾concentration phase End (g/10 (cc · mm/(m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ masking³⁾ minutes) day · atm))Polyamide 1H 17.5 MXDA Sebacic acid (0.4) ∘ x 11.0 0.34 (0.992) Adipicacid (0.6) (4 hours) (240° C.) Polyamide 2H 19.2 MXDA Sebacic acid (0.7)∘ x 10.1 0.68 (0.992) Adipic acid (0.3) (4 hours) (240° C.) Polyamide 3H19.5 MXDA Sebacic acid (0.3) ∘ x 10.5 0.21 (0.992) Adipic acid (0.7) (4hours) (240° C.) Polyamide 4H 19.8 MXDA Adipic acid (1.0) ∘ x 14.4 0.09(0.994) (4 hours) (250° C.) Polyamide 5H 23.5 MXDA Adipic acid (1.0) x ∘35.7 0.13 (0.8) (270° C.) PXDA (0.2) Polyamide 6H 14.8 MXDA Adipic acid(0.9) ∘ x 15.4 0.08 (0.991) Isophthalic acid (0.1) (4 hours) (250° C.)Polyamide 7H 42.4 MXDA Adipic acid (1.0) ∘ x 14.1 0.09 (1.0) (4 hours)(250° C.) Polyamide 8H 31.4 MXDA Adipic acid (1.0) ∘ x 31.2 0.09 (0.994)(2 hours) (250° C.) MXDA: metaxylylenediamine, PXDA: paraxylylenediamine¹⁾Numerical value in parentheses shows a mole ratio of each component.²⁾∘: the solid phase polymerization was carried out. The polymerizationtime is shown in parentheses. x: the solid phase polymerization was notcarried out. ³⁾∘: the end amino group was masked. x: the end amino groupwas not masked. ⁴⁾A non-stretched film was prepared from the polyamidealone, and an oxygen permeability coefficient thereof was measured at23° C. and 60% RH.

TABLE 2H Composition Polyamide Sealing Color (end amino Melting Filmstrength tone Flavor group kneading roll after boiling Oxygen afterafter concentration ratio¹⁾ appearance (kg/15 mm) concentration 1 month1 month Example 1H Polyamide 1H 40:50:10 Good 5.1 0.1% or less Good Good(17.5 μeq/g) Example 2H Polyamide 1H 40:55:5 Good 4.8 0.1% or less GoodGood (17.5 μeq/g) Example 3H Polyamide 1H 40:45:15 Good 5.3 0.8% GoodGood (17.5 μeq/g) Example 4H Polyamide 1H 40:35:25 Good 5.4 1.4% AlmostAlmost (17.5 μeq/g) good good Example 5H Polyamide 1H 55:35:10 Slightly4.7 0.7% Good Good (17.5 μeq/g) inferior Example 6H Polyamide 1H 25:70:5Good 5.5 1.7% Almost Almost (17.5 μeq/g) good good Example 7H Polyamide2H 40:50:10 Good 5.2 0.1% or less Good Good (19.2 μeq/g) Example 8HPolyamide 3H 40:50:10 Good 5.3 0.1% or less Good Good (19.5 μeq/g)Example 9H Polyamide 4H 40:50:10 Good 5.0 0.9% Good Good (19.8 μeq/g)Example 10H Polyamide 5H 40:50:10 Slightly 4.7 1.0% Almost Almost (23.5μeq/g) inferior good good Example 11H Polyamide 6H 40:50:10 Good 5.10.5% Good Good (14.8 μeq/g) Comparative Polyamide 1H 10:85:5 Good 5.28.0% Discolored Flavor Example 1H (17.5 μeq/g) reduced ComparativePolyamide 1H 70:20:10 Slightly 4.0 7.1% Discolored Flavor Example 2H(17.5 μeq/g) inferior reduced Comparative Polyamide 7H 40:50:10 Good 5.09.5% Discolored Flavor Example 3H (42.4 μeq/g) reduced ComparativePolyamide 8H 40:50:10 Inferior 3.8 8.5% Discolored Flavor Example 4H(31.4 μeq/g) reduced ¹⁾(total weight of transition metal catalyst andpolyamide resin):weight of polyolefin resin:weight of modifiedpolyolefin resin

As apparent from Examples 1H to 11H, the oxygen-absorbing multilayerfilms of the present invention were excellent in an oxygen-absorbingperformance, a processability and a strength and can maintain a highsealing strength in processing them into bags and the like, andtherefore they are suited to heating treatment applications such asboiling treatment and the like. They had an inside visibility andtherefore made it possible to confirm a color tone of the content.

On the other hand, in Comparative Example 3H in Which a mole ratio ofMXDA to adipic acid was increased and Comparative Example 4H in whichthe solid phase polymerization time was shortened as compared withExample 9H, the end amino group concentration exceeded 30 μeq/g, and thegood oxygen-absorbing performance was not obtained. Further, anappearance of the film was deteriorated as well in Comparative Example4H.

The present invention provides the oxygen-absorbing multilayer filmswhich are excellent in an oxygen-absorbing performance at a low humidityand a high humidity and maintain a resin strength after stored and whichare excellent in a processability and an interlayer strength an can beapplied to various containers and uses by preparing the multilayer filmshaving an oxygen-absorbing resin layer prepared by blending the specificpolyamide resin and the transition metal catalyst with the polyolefinresin and the modified polyethylene resin in a specific proportion.

Example 12H

An oxygen-absorbing resin pellet B was obtained in the same manner as inExample 1H, except that an ethylene-propylene block copolymer (productname: “Novatec PP BC3HF” manufactured by Japan PolypropyleneCorporation, MFR: 8.5 g/10 minutes at 230° C., MFR: 10.8 g/10 minutes at240° C., hereinafter referred to as PP 1) was used in place of LLDP 1. Atwo kind, three layer film (thickness: intermediate PP 1 layer 20μm/oxygen-absorbing resin layer 30 μm/sealant PP 1 layer 20 μm) in whichthe oxygen-absorbing resin pellet B obtained was used for anoxygen-absorbing resin layer and in which PP 1 was used for a sealantlayer and an intermediate layer was subjected on an intermediate layersurface thereof to corona discharge treatment in a width of 800 mm at 30m/minute to prepare a film roll thereof. Uneven thickness such as humpsand the like was not observed on the film roll, and it had a goodappearance and a HAZE of 85%. A urethane base adhesive for dry laminate(product name: “AD-817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.)was used to laminate a nylon film A and a silica-deposited PET film(product name: “Tech Barrier T” manufactured by Mitsubishi Plastics,Inc.) on a corona discharge-treated surface side to obtain anoxygen-absorbing multilayer film comprising an oxygen-absorbingmultilayer film of a silica-deposited PET film (12)/adhesive (3)/nylonfilm A (15)/adhesive (3)/PP 1 (20)/oxygen-absorbing resin (30)/PP 1(20). Then, the film was processed into a self-supported bag (13 cm×19cm×3 cm) comprising two side face films and one bottom face film with asealant layer side turned to an inner face to find that a processabilityof the bag was good. The 100 bags charged with curry containing carrot,potato and meat and tightly sealed were subjected to retort treatment at121° C. for 30 minutes to measure a sealing strength thereof after theretort treatment. Then, they were stored at 23° C. to inspect a flavorof the curry after one month. The results thereof are shown in Table 3H.

Example 13H

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 12H, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1H:PP 1:MAPE=40:40:20. Then, a self-supported bag was prepared to carry out thesame storing test as in Example 12H. The results thereof are shown inTable 3H.

TABLE 3H Composition Polyamide Sealing (end amino Modified Meltingstrength Flavor group polyolefin kneading after after concentrationresin ratio¹⁾ retort 1 month Example Polyamide 1H MAPE 40:50:10 4.8 kg/Good 12H (17.5 μeq/g) 15 mm Example Polyamide 1H MAPE 40:40:20 5.1 kg/Good 13H (17.5 μeq/g) 15 mm MAPE: maleic anhydride-modified polyethyleneMAPP: maleic anhydride polypropylene ¹⁾(total weight of transition metalcatalyst and polyamide resin):weight of polyolefin resin:weight ofmodified polyolefin resin

The present invention provides the oxygen-absorbing multilayer filmswhich maintain a resin strength and are excellent in an interlayerstrength by preparing the multilayer films having an oxygen-absorbingresin layer prepared by blending the specific polyamide resin and thetransition metal catalyst with the polyolefin resin and the modifiedpolyethylene resin in a specific proportion.

Example 1J

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.993:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1J). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 1J had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 18.8 μeq/g, an end carboxylgroup concentration of 85.6 μeq/g, a number average molecular weight of23000 and MFR of 11.4 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 1J alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1J through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1J) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Harmolex NC564A” manufactured by Japan PolyethyleneCorporation, MFR: 3.5 g/10 minutes (measured according to JIS K7210),MFR: 7.5 g/10 minutes at 240° C., MFR: 8.7 g/10 minutes at 250° C.,hereinafter referred to as LLDPE) as a polyolefin resin in a weightratio of the cobalt stearate-containing polyamide 1J: LLDPE=35:65 toobtain a pellet comprising an oxygen-absorbing resin composition.

A two kind, three layer film (thickness: 10 μm/20 μm/10 μm) in which theoxygen-absorbing resin composition obtained was used for anoxygen-absorbing resin layer and in which LLDPE was used for a sealantlayer and an intermediate layer was prepared by subjecting anintermediate layer surface thereof to corona discharge treatment in awidth of 800 mm at 100 m/minute. The film thus obtained had a goodappearance and a HAZE of 20%. A urethane base adhesive for dry laminate(product name: “AD-817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.)was used on a corona discharge-treated surface side to obtain anoxygen-absorbing multilayer film comprising an oxygen-absorbingmultilayer film of an aluminum-deposited PET film (product name:“GL-ARH”-F manufactured by Toppan Printing Co., Ltd.)/adhesive (3)/nylon(product name: “N1202” manufactured by Toyobo Co., Ltd., 15)/adhesive(3)/LLDPE (10)/oxygen-absorbing resin composition (20)/LLDPE (10). Theabove oxygen-absorbing multilayer film was used to prepare a threeside-sealed bag of 10×15 cm, and the bag was charged with 100 g of apowder seasoning “Ajinomoto” having a water activity of 0.35 and tightlysealed. Then, it was stored at 23° C. An oxygen concentration in the bagand a flavor of the powder seasoning in the seventh day and after storedfor one month were inspected. The results thereof are shown in Table 2J.

Example 2J

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1J, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1J: LLDPE=55:45.Then, a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Example 3J

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1J, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1J: LLDPE=25:75.Then, a three side-sealed bag was prepared to carry out the same storingtest as in Example 1G. The results thereof are shown in Table 2G.

Example 4J

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2J). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 2J had Tg of 78° C., amelting point of 194° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.5 μeq/g, an end carboxylgroup concentration of 81.2 μeq/g, a number average molecular weight of24500 and MFR of 10.5 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 2J alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.21cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 2J, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1J toobtain an oxygen-absorbing resin pellet. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1J, andthen a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Example 5J

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 3J). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 3J had Tg of 65° C., amelting point of 170° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.2 μeq/g, an end carboxylgroup concentration of 80.0 μeq/g, a number average molecular weight of25200 and MFR of 10.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 3J alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.84cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 3J, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1J toobtain an oxygen-absorbing resin pellet. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1J, andthen a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Example 6J

Metaxylylenediamine:adipic acid:isophtalic acid were used in a moleratio of 0.991:0.9:0.1 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 4J). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 205°C. and the polymerization time to 4 hours. The above polyamide 4J had Tgof 94° C., a melting point of 228° C., a semi-crystallization time of300 seconds, an end amino group concentration of 14.8 μeq/g, an endcarboxyl group concentration of 67.2 μeq/g and a number averagemolecular weight of 23000. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 15.4 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 4J alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.08cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4J, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1J toobtain an oxygen-absorbing resin pellet, except that the temperature inmelting and kneading was changed to 250° C. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1J, andthen a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Example 7J

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.998:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin, and then an end amino group concentration thereof wasmeasured (the end amino group concentration was 33.6 μeq/g). Next,phthalic anhydride was added thereto as an end masking agent in anamount of 1.5 equivalent based on the above end amino groupconcentration. Then, the mixture was molten and kneaded at 200° C. bymeans of a biaxial extruding equipment, and the end amino group wasmasked to synthesize a polyamide resin (hereinafter, the above polyamideresin is referred to as the polyamide 5J). Controlled were the dropwiseadding time to 2 hours, the reaction time in the melt polymerization to1 hour, the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 160°C. and the polymerization time to 4 hours. The polyamide 5J had Tg of73° C., a melting point of 184° C., a semi-crystallization time of 2000seconds or longer, an end amino group concentration of 15.8 μeq/g, anend carboxyl group concentration of 63.0 μeq/g, a number averagemolecular weight of 23200 and MFR of 13.0 g/10 minutes at 240° C.Further, a non-stretched film was prepared from the resulting polyamide5J alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.74 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 5J, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1J toobtain an oxygen-absorbing resin pellet. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1J, andthen a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Example 8J

Metaxylylenediamine and paraxylylenediamine were mixed in 7:3, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin, and then an end aminogroup concentration thereof was measured (the end amino groupconcentration was 35.7 μeq/g). Next, phthalic anhydride was addedthereto as an end masking agent in an amount of 1.5 equivalent based onthe above end amino group concentration. Then, the mixture was moltenand kneaded at 200° C. by means of a biaxial extruding equipment, andthe end amino group was masked to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide6J). Controlled were the dropwise adding time to 2 hours, thepolymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 277° C. and thereaction time to 30 minutes. The above polyamide 6J had Tg of 87° C., amelting point of 259° C., a semi-crystallization time of 18 seconds, anend amino group concentration of 25.8 μeq/g, an end carboxyl groupconcentration of 75.6 μeq/g and a number average molecular weight of18500. MFR could not be measured at 250° C. since it was close to themelting point, and MFR at 270° C. was measured to find that MFR at 270°C. was 29.8 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 6J alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 6J, and the mixture wasmolten and kneaded with LLDPE in the same manner as in Example 1J toobtain an oxygen-absorbing resin pellet, except that the temperature inmelting and kneading was changed to 270° C. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1J, andthen a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Comparative Example 1J

An oxygen-absorbing multilayer film was produced in the same manner asin Example 1J, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1J: LLDPE=80:20.Then, a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Comparative Example 2J

An oxygen-absorbing multilayer film was produced in the same manner asin Example 1J, except that the mixture was not molten and not kneadedwith LLDPE and that the film was prepared only from the cobaltstearate-containing polyamide 1J. Then, a three side-sealed bag wasprepared to carry out the same storing test as in Example 1J. Theresults thereof are shown in Table 2J.

Comparative Example 3J

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 7J) was synthesized in the same manner as in Example4J, except that metaxylylenediamine:sebacic acid:adipic acid were usedin a mole ratio of 0.998:0.4:0.6 and not subjected to solid phasepolymerization. The above polyamide 7J had Tg of 73° C., a melting pointof 184° C., a semi-crystallization time of 2000 seconds or longer, anend amino group concentration of 39.1 μeq/g, an end carboxyl groupconcentration of 70.2 μeq/g and a number average molecular weight of17800. MFR at 240° C. was 51.0 g/10 minutes. Further, a non-stretchedfilm was prepared from the resulting polyamide 7J alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 7J, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1J toobtain an oxygen-absorbing resin pellet. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1J, andthen a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

Comparative Example 4J

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 8J) was synthesized in the same manner as in Example4J, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.999:1 and that a polymerization time in the solid phasepolymerization was changed to 2 hours. The above polyamide 8J had Tg of78° C., a melting point of 237° C., a semi-crystallization time of 25seconds, an end amino group concentration of 34.8 μeq/g, an end carboxylgroup concentration of 58.6 μeq/g and a number average molecular weightof 21800. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 260° C. was measured to find that MFR at 260°C. was 18.9 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 8J alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 8J, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1J toobtain an oxygen-absorbing resin pellet, except that the temperature inmelting and kneading was changed to 260° C. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1J, andthen a three side-sealed bag was prepared to carry out the same storingtest as in Example 1J. The results thereof are shown in Table 2J.

The respective details of the polyamides 1J to 8J obtained above areshown in Table 1J, and the results of the respective examples andcomparative examples are shown in Table 2J.

TABLE 1J Oxygen End amino permeability group Solid MFR coefficientconcentration phase End (g/10 (cc · mm/(m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ masking³⁾ minutes) day · atm))Polyamide 1J 18.8 MXDA Sebacic acid (0.4) ∘ x 11.4 0.34 (0.993) Adipicacid (0.6) (4 hours) (240° C.) Polyamide 2J 19.5 MXDA Sebacic acid (0.3)∘ x 10.5 0.21 (0.992) Adipic acid (0.7) (4 hours) (240° C.) Polyamide 3J19.2 MXDA Sebacic acid (0.7) ∘ x 10.1 0.84 (0.992) Adipic acid (0.3) (4hours) (240° C.) Polyamide 4J 14.8 MXDA Adipic acid (0.9) ∘ x 15.4 0.08(0.991) Isophthalic acid (0.1) (4 hours) (250° C.) Polyamide 5J 15.8MXDA Sebacic acid (0.4) ∘ ∘ 13.0 0.74 (0.998) Adipic acid (0.6) (4hours) (240° C.) Polyamide 6J 25.8 MXDA Adipic acid (1.0) x ∘ 29.8 0.13(0.7) (270° C.) PXDA (0.3) Polyamide 7J 39.1 MXDA Sebacic acid (0.4) x x51.0 0.34 (0.998) Adipic acid (0.6) (240° C.) Polyamide 8J 34.8 MXDAAdipic acid (1.0) ∘ x 18.9 0.09 (0.999) (2 hours) (260° C.) MXDA:metaxylylenediamine, PXDA: paraxylylenediamine ¹⁾Numerical value inparentheses shows a mole ratio of each component. ²⁾∘: the solid phasepolymerization was carried out. The polymerization time is shown inparentheses. x: the solid phase polymerization was not carried out. ³⁾∘:the end amino group was masked. x: the end amino group was not masked.⁴⁾A non-stretched film was prepared from the polyamide alone, and anoxygen permeability coefficient thereof was measured at 23° C. and 60%RH.

TABLE 2J Film Composition Oxygen Polyamide Melting concentration Flavor(end amino group kneading Appearance After after concentration ratio¹⁾of roll 7th day 1 month 1 month Example 1J Polyamide 1J 35:65 Good 0.8%0.1% Good (18.8 μeq/g) or less Example 2J Polyamide 1J 55:45 Good 3.8%0.3% Almost (18.8 μeq/g) good Example 3J Polyamide 1J 25:75 Good 1.2%0.1% Good (18.8 μeq/g) or less Example 4J Polyamide 2J 35:65 Good 0.9%0.1% Good (19.5 μeq/g) or less Example 5J Polyamide 3J 35:65 Good 0.9%0.1% Good (19.2 μeq/g) or less Example 6J Polyamide 4J 35:65 Good 4.2%0.7% Almost (14.8 μeq/g) good Example 7J Polyamide 5J 35:65 Good 0.2%0.1% Good (15.8 μeq/g) or less Example 8J Polyamide 6J 35:65 Slightly5.8% 1.3% Almost (25.8 μeq/g) inferior good Comparative Polyamide 1J80:20 Slightly 9.0% 4.0% lowered Example 1J (18.8 μeq/g) inferiorComparative Polyamide 1J 100:0  Good 9.1% 4.3% lowered Example 2J (18.8μeq/g) Comparative Polyamide 7J 35:65 Slightly 9.7% 3.2% lowered Example3J (39.1 μeq/g) inferior Comparative Polyamide 8J 35:65 Slightly 8.3%4.1% lowered Example 4J (34.8 μeq/g) inferior ¹⁾(total weight oftransition metal catalyst and polyamide resin): weight of polyolefinresin

Example 9J

The oxygen-absorbing multilayer film obtained in Example 1J was used,and this film was processed into a self-supported bag (130×175×35 mm)comprising two side face films and one bottom face film with anintermediate layer side turned to an inner face to find that aprocessability of the bag was good. The bag was charged with radishestogether with a solution containing acetic acid in a total amount of 200g by high speed automatic charging at a rate of 40 bags/minute to findthat an opening property of the bag was good and that heat sealingthereof could be carried out without having any problems. The 100 bagswhich were charged and tightly sealed were subjected to boilingtreatment at 90° C. for 30 minutes and then stored at 23° C. to inspecta flavor of the radishes, a concentration of oxygen in the bags and anappearance of the self-supported bags after one month. The radishescould be visually confirmed from an outside of the bags, and a flavorand a color tone of the radishes were maintained well. An appearance ofthe bags was not abnormal, and a concentration of oxygen in the bags was0.1% or less.

Example 10J

A two kind, three layer film (thickness: 10 μm/20 μm/40 μm) in which theoxygen-absorbing resin composition obtained in Example 1J was used foran oxygen-absorbing layer and in which LLDPE was used for a sealantlayer and an intermediate layer was prepared by subjecting anintermediate layer surface thereof to corona discharge treatment in awidth of 800 mm at 80 m/minute. The film thus obtained was reducedslightly in an appearance as compared with the two kind, three layerfilm 1, and a HAZE thereof was 30%. A urethane base adhesive for drylaminate (product name: “AD-817/CAT-RT86L-60” manufactured byToyo-Morton, Ltd.) was used on a corona discharge-treated surface sideto obtain an oxygen-absorbing multilayer film comprising anoxygen-absorbing multilayer film of an aluminum-deposited PET film(product name: “GL-ARH”-F manufactured by Toppan Printing Co.,Ltd.)/adhesive (3)/nylon (product name: “N1202” manufactured by ToyoboCo., Ltd., 15)/adhesive (3)/LLDPE (40)/oxygen-absorbing resincomposition (20)/LLDPE (10). Numbers in parentheses mean a thickness(unit: μm) of the respective layers. Then, the bag was charged withradishes together with a solution containing acetic acid in a totalamount of 200 g in the same manner as in Example 9J to find that heatsealing thereof could be carried out without having any problems. Thebag which was charged was subjected as it was to boiling treatment at90° C. for 30 minutes and then stored at 23° C. to inspect a flavor ofthe radishes, a concentration of oxygen in the bag and an appearance ofthe self-supported bag after one month. A flavor and a color tone of theradishes were maintained well, and a concentration of oxygen in the bagwas 0.1% or less, but the bag was reduced slightly in an appearance.

Example 11J

A two kind, three layer film 1 was prepared in the same manner as inExample 1J, and this was used to obtain an oxygen-absorbing multilayerpaper base material of bleached craft paper (basis weight: 340g/m²)/urethane base adhesive for dry laminate (product name:“AD817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.,3)/aluminum-deposited PET film (product name: “GL-ARH-F” manufactured byToppan Printing Co., Ltd., 12)/urethane base anchor coating agent(product name: “EL-557A/B” manufactured by Toyo-Morton, Ltd., 0.5)/lowdensity polyethylene (20)/LLDPE (10)/oxygen-absorbing resin composition(20)/LLDPE (10) by extrusion lamination using low density polyethylene(product name: “Milason 18SP” manufactured by Mitsui Chemicals, Inc.).The above base material was molded into a paper container of a gable toptype for 1 liter. A moldability of the container was good. The abovepaper container was charged with distilled barley spirit and tightlysealed, and then it was stored at 23° C. An oxygen concentration in thepaper container was 0.1% or less after one month, and a flavor of thedistilled barley spirit was maintained well.

Example 12J

An oxygen-absorbing resin pellet was obtained in the same manner as inExample 1J, except that an ethylene-propylene block copolymer (productname: “Novatec FG3DC” manufactured by Japan Polypropylene Corporation,MFR: 9.5 g/10 minutes at 230° C., MFR: 10.6 g/10 minutes at 240° C.,hereinafter referred to as PP) was used in place of LLDP. Then, a twokind, three layer film (thickness: 15 μm/30 μm/15 μm) was prepared inthe same manner as in Example 1J, except that the above oxygen-absorbingresin pellet was used for a core layer and that PP was used for asealant layer and an intermediate layer in place of LLDPE. A HAZE of thefilm thus obtained was 66%. The urethane base adhesive for dry laminate(product name: “AD817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.)was used for a corona discharge-treated surface to obtain anoxygen-absorbing multilayer film of aluminum-deposited PET (productname: “GL-ARH-F” manufactured by Toppan Printing Co., Ltd., 12)/adhesive(3)/nylon (product name: “N1202” manufactured by Toyobo Co., Ltd.,15)/adhesive (3)/PP (15)/oxygen-absorbing resin composition (30)/PP(15). The above oxygen-absorbing multilayer film was used to prepare athree side-sealed bag of 10×20 cm. A circular vapor-passing port havinga diameter of 2 mm was provided on a part thereof, and a circumferenceof the vapor-passing port was tentatively adhered by a label seal. Thebag was charged with beef stew containing carrot and meat and tightlysealed, and then it was stored at 23° C. after subjected to retortcooking and thermal sterilization at 124° C. for 30 minutes. The beefstew in an inside of the bag could be visually confirmed. After onemonth, the bag was heated as it was for about 4 minutes in an electricoven, and the bag was swollen after about 3 minutes to confirm that thetentatively adhered label seal was peeled off and that vapor wasdischarged from the vapor-passing port. After finishing cooking, aflavor of the beef stew and a color tone of the carrot were inspected tofind that an appearance of the carrot was maintained well and that aflavor of the beef stew was good.

Comparative Example 5J

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith LLDPE in a weight ratio of 30:70 to obtain an iron powder baseoxygen-absorbing resin composition AJ. A two kind, three layer film wastried to be prepared in the same manner as in Example 1J by using theiron powder base oxygen-absorbing resin composition AJ for a core layer,but irregularities of the iron powder were generated on a film surface,and the film was not obtained. Accordingly, the iron powder baseoxygen-absorbing resin composition AJ was extruded and laminated as anoxygen-absorbing layer in a thickness of 20 μm on LLDPE having athickness of 40 μm to obtain a laminated film which was subjected on anoxygen-absorbing layer surface to corona discharge treatment. The abovelaminated film was laminated on a bleached craft paper in the samemanner as in Example 11J to try to prepare a paper container of a gabletop type comprising an oxygen-absorbing multilayer paper base materialof bleached craft paper (basis weight: 340 g/m²)/urethane base adhesivefor dry laminate (product name: “AD817/CAT-RT86L-60” manufactured byToyo-Morton, Ltd., 3)/aluminum-deposited PET film (product name:“GL-ARH-F” manufactured by Toppan Printing Co., Ltd., 12)/urethane baseanchor coating agent (product name: “EL-557A/B” manufactured byToyo-Morton, Ltd., 0.5)/low density polyethylene (product name: “Milason18SP” manufactured by Mitsui Chemicals, Inc., 20)/iron powder baseoxygen-absorbing resin composition AJ (20)/LLDPE (40), but the thicknesswas large, and it was difficult to prepare a corner of the papercontainer. A preparing speed of the containers was reduced to cut offthe rejected products, and the containers were obtained at last. Astoring test of distilled barley spirit was carried out in the samemanner as in Example 11J, but aldehyde odor was generated in opening thecontainer, and a flavor thereof was notably reduced.

Comparative Example 6J

An iron powder base oxygen-absorbing resin composition BJ was obtainedin the same manner as in Comparative Example 6J, except that PP was usedin place of LLDPE. Further, a laminated film of the iron powder baseoxygen-absorbing resin composition BJ (20)/PP (40) was prepared in thesame manner as in Comparative Example 5J, except that PP was used inplace of LLDPE, and then the oxygen-absorbing layer surface wassubjected to corona discharge treatment. Then, an oxygen-absorbingmultilayer film of aluminum-deposited PET (product name: “GL-ARH-F”manufactured by Toppan Printing Co., Ltd., 12)/adhesive (3)/nylon(product name: “N1202” manufactured by Toyobo Co., Ltd., 15)/adhesive(3)/iron powder base oxygen-absorbing resin composition BJ (20)/PP (40)was obtained in the same manner as in Example 12J. The oxygen-absorbingmultilayer film thus obtained was used to carry out the same test as inExample 12J to result in finding that a flavor of the beef stew wasmaintained well but the content could not be visually confirmed and thatair bubble-like unevenness was generated on the surface in heating in anelectric oven.

As apparent from Examples 1J to 10J, the oxygen-absorbing resinmultilayer films of the present invention were excellent in anoxygen-absorbing performance, a processability and a strength and had aninside visibility.

In contrast with this, the oxygen-absorbing performance wasunsatisfactory in Comparative Examples 1J and 2J in which a content ofthe polyamide A in the resin composition exceeded 60% by weight. Inparticular, as apparent from comparison of Comparative Examples 1J and2J with Examples 1J to 3J, the good oxygen-absorbing performances werenot necessarily obtained when a content of the polyamide A in the resincomposition was large.

On the other hand, in Comparative Example 4J in which the solid phasepolymerization was not carried out and Comparative Example 4J in whichthe solid phase polymerization time was shortened, an end amino groupconcentration of the polyamide resin obtained exceeded 30 μeq/g, and thegood oxygen-absorbing performance was not obtained in comparison withExample 1J. Further, an appearance of the film roll was deteriorated aswell.

As apparent from Examples 1J to 12J, the oxygen-absorbing resincompositions of the present invention were excellent in a processabilityinto the paper containers and provided storing containers which werefavorable in storing alcoholic beverages and heating and cooking by anelectric oven even if a vapor-passing port was mounted. Further, theyhad an inside visibility, and a color tone of the content could beconfirmed.

The present invention relates to the oxygen-absorbing multilayer filmswhich maintain a resin strength and which are excellent in an interlayerstrength by providing an intermediate layer comprising a polyolefinresin between both layers of a multilayer film having anoxygen-absorbing resin layer prepared by blending the specific polyamideresin and the transition metal catalyst with a polyolefin resin in aspecific proportion and a gas-barriering layer.

Production of Epoxy Resin Curing Agent a:

A reaction container was charged with 1 mole of metaxylylenediamine. Thereaction container was heated up to 60° C. under nitrogen flow, and 0.93mole of methyl acrylate was dropwise added thereto in one hour. Afterfinishing dropwise adding, the mixture was stirred at 120° C. for onehour, and the reaction container was further heated up to 160° C. in 3hours while removing formed methanol by distillation. The mixture wascooled down to 100° C., and a prescribed amount of methanol was addedthereto so that a solid matter concentration was controlled to 70% byweight to obtain an epoxy resin curing agent a. A content of an amidegroup in the epoxy resin curing agent a was 21% by weight.

Example 1K

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1K). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 1K had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 17.5 μeq/g, an end carboxylgroup concentration of 91.6 μeq/g, a number average molecular weight of23500 and MFR of 11.0 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 1K alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1K through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1K) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Kernel KF380” manufactured by Japan PolyethyleneCorporation, MFR: 4.0 g/10 minutes (measured according to JIS K7210),MFR: 8.7 g/10 minutes at 240° C., MFR: 10.0 g/10 minutes at 250° C.,hereinafter referred to as LLDPE) as a polyolefin resin in a weightratio of the cobalt stearate-containing polyamide 1K:LLDPE=35:65 toobtain an oxygen-absorbing resin composition. Then, the aboveoxygen-absorbing resin composition was used to prepare a two kind, threelayer film 1 (thickness: 10 μm/20 μm/10 μm) in which LLDPE was used fora skin layer by subjecting one surface thereof to corona dischargetreatment in a width of 800 mm at 120 m/minute. An appearance of thefilm thus obtained was good, and HAZE thereof was 14%.

A methanol/ethyl acetate=9/1 solution (solid matter concentration: 35%by weight) containing 57 parts by weight of an epoxy resin (TETRAD-X,manufactured by Mitsubishi Gas Chemicals, Inc.) having a glycidylaminepart derived from metaxylylenediamine and 182 parts by weight of anepoxy resin curing agent a was prepared, and 0.4 part by weight of anacryl base wetting agent (BYK381, manufactured by BYK Chemie A.G.) and0.1 part by weight of a silicone base defoaming agent (BYK065,manufactured by BYK Chemie A.G.) were added thereto and stirred well toobtain a coating liquid (epoxy resin composition) in which an equivalentratio (active hydrogen/epoxy group) of active hydrogen in the epoxyresin curing agent to an epoxy group in the epoxy resin was 1.2. Astretched nylon film (N-1201, manufactured by Toyobo Co., Ltd.) having athickness of 15 μm was used for an outer layer, and the coating liquidwas coated on a corona-treated surface of the outer layer and dried at90° C. for 5 seconds. Then, the film 1 was laminated thereon to obtainan oxygen-absorbing multilayer film 1 comprising LLDPE/oxygen-absorbinglayer/LLDPE/epoxy resin-cured matter layer/outer layer. A content of theskeletal structure represented by Formula (1) in the epoxy resin-curedmatter layer was 62.0% by weight.

A three side-sealed bag of 13×18 cm was prepared from theoxygen-absorbing multilayer film 1 obtained, and it was charged with 60g of pineapple and 120 g of a syrup liquid and tightly sealed so that ahead space air amount was 20 cc. It was subjected to heatingsterilization treatment at 85° C. for 90 minutes to measure a head spaceoxygen concentration immediately after the heating treatment. Then, acolor tone of the pineapple and a sealing strength of one side of thethree side-sealed bag in storing at 40° C. for 2 months were measured.The results thereof are shown in Table 2K.

Example 2K

An oxygen-absorbing multilayer film was produced in the same manner asin Example 1K, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1K:LLDPE=55:45, andthe bag was charged with pineapple and subjected to heating treatment tomeasure an oxygen concentration immediately after the heating treatmentand a flavor thereof and a sealing strength of the bag after one month.The results thereof are shown in Table 2K.

Example 3K

An oxygen-absorbing multilayer film was produced in the same manner asin Example 1K, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1K:LLDPE=25:75, andthe bag was charged with pineapple and subjected to heating treatment tomeasure an oxygen concentration immediately after the heating treatmentand a flavor thereof and a sealing strength of the bag after one month.The results thereof are shown in Table 2K.

Example 4K

Metaxylylenediamine:adipic acid were used in a mole ratio of 0.991:1 andsubjected to melt polymerization and solid phase polymerization on thesynthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide2K). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 4hours. The above polyamide 2K had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 19.8 μeq/g, an end carboxyl group concentration of 68.6μeq/g and a number average molecular weight of 23000. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 14.4 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 2K alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 2K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, except that the temperaturein melting and kneading was changed to 250° C., and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Example 5K

Metaxylylenediamine and paraxylylenediamine were mixed in 7:3, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 285° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 3K). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 277° C. and thereaction time to 30 minutes. The above polyamide 3K had Tg of 87° C., amelting point of 255° C., a semi-crystallization time of 18 seconds, anend amino group concentration of 25.8 μeq/g, an end carboxyl groupconcentration of 65.6 μeq/g and a number average molecular weight of18500. MFR could not be measured at 250° C. since it was close to themelting point, and MFR at 260° C. was measured to find that MFR at 260°C. was 29.8 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 3K alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 3K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, except that the temperaturein melting and kneading was changed to 265° C., and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Example 6K

Metaxylylenediamine, adipic acid and isophthalic acid were used in amole ratio of 0.991:0.8:0.2 and subjected to melt polymerization andsolid phase polymerization on the synthetic conditions described aboveto synthesize a polyamide resin (hereinafter, the above polyamide resinis referred to as the polyamide 4K). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 215°C. and the polymerization time to 4 hours. The above polyamide 4K had Tgof 92° C., a melting point of 230° C., a semi-crystallization time of250 seconds, an end amino group concentration of 14.8 μeq/g, an endcarboxyl group concentration of 67.2 μeq/g and a number averagemolecular weight of 23000. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 17.4 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 4K alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.07cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, except that the temperaturein melting and kneading was changed to 250° C., and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Example 7K

Metaxylylenediamine and sebacic acid were used in a mole ratio of0.994:1 and subjected only to melt polymerization on the syntheticconditions described above to synthesize a polyamide resin (hereinafter,the above polyamide resin is referred to as the polyamide 5K).Controlled were the dropwise adding time to 2 hours and the reactiontime in the melt polymerization to 1 hour. The above polyamide 5K had Tgof 61° C., a melting point of 190° C., a semi-crystallization time of150 seconds, an end amino group concentration of 24.8 μeq/g, an endcarboxyl group concentration of 57.2 μeq/g, a number average molecularweight of 17200 and MFR of 65.4 g/10 minutes at 240° C. A non-stretchedfilm was prepared from the resulting polyamide 5K alone, and an oxygenpermeability coefficient thereof was determined to find that it was 1.58cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 5K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Example 8K

Metaxylylenediamine, adipic acid and isophthalic acid were used in amole ratio of 0.998:0.95:0.05 and subjected to melt polymerization andsolid phase polymerization on the synthetic conditions described aboveto synthesize a polyamide resin (hereinafter, the above polyamide resinis referred to as the polyamide 6K). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 215°C. and the polymerization time to 20 hours. The above polyamide 6K hadTg of 92° C., a melting point of 230° C., a semi-crystallization time of250 seconds, an end amino group concentration of 28.8 μeq/g, an endcarboxyl group concentration of 61.8 μeq/g, a number average molecularweight of 24200 and MFR of 10.1 g/10 minutes at 240° C. A non-stretchedfilm was prepared from the resulting polyamide 6K alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.08cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Example 9K

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.998:0.6:0.4 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin. Controlled were the dropwise adding time to 2 hours,the reaction time in the melt polymerization to 1 hour, the pressure inan inside of the equipment in the solid phase polymerization to 1 torror less, the polymerization temperature to 150° C. and thepolymerization time to 8 hours. Then, phthalic anhydride 0.2 wt % wasadded thereto, and the mixture was molten and kneaded at 250° C. bymeans of a biaxial extruding equipment to mask an end amino group(hereinafter, the above polyamide resin is referred to as the polyamide7K). The above polyamide 7K had Tg of 70° C., a melting point of 157°C., a semi-crystallization time of 18 seconds, an end amino groupconcentration of 15.8 μeq/g, an end carboxyl group concentration of 51.6μeq/g, a number average molecular weight of 23000 and MFR of 11.4 g/10minutes at 240° C. A non-stretched film was prepared from the resultingpolyamide 7K alone, and an oxygen permeability coefficient thereof wasdetermined to find that it was 0.74 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 7K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Example 10K

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 8K). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 8K had Tg of 78° C., amelting point of 194° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.5 μeq/g, an end carboxylgroup concentration of 81.2 μeq/g, a number average molecular weight of24500 and MFR of 10.5 g/10 minutes at 240° C. A non-stretched film wasprepared from the resulting polyamide 8K alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.21cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 8K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Example 11K

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 9K). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 9K had Tg of 65° C., amelting point of 170° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 19.2 μeq/g, an end carboxylgroup concentration of 80.0 μeq/g, a number average molecular weight of25200 and MFR of 10.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 9K alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.68cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 9K, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1K toproduce an oxygen-absorbing multilayer film, and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Comparative Example 1K

A film was produced in the same manner as in Example 1K to produce anoxygen-absorbing multilayer film, except that the weight ratio inmelting and kneading was changed to the cobalt stearate-containingpolyamide 1:LLDPE=80:20, and the bag was charged with pineapple andsubjected to heating treatment to measure an oxygen concentrationimmediately after the heating treatment and a flavor thereof and asealing strength of the bag after one month. The results thereof areshown in Table 2K.

Comparative Example 2K

A film was produced in the same manner as in Example 1K to produce anoxygen-absorbing multilayer film, except that the weight ratio inmelting and kneading was changed to the cobalt stearate-containingpolyamide 1K:LLDPE=10:90, and the bag was charged with pineapple andsubjected to heating treatment to measure an oxygen concentrationimmediately after the heating treatment and a flavor thereof and asealing strength of the bag after one month. The results thereof areshown in Table 2K.

Comparative Example 3K

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 10K) was synthesized in the same manner as in Example4K, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.998:1 and not subjected to solid phase polymerization. Theabove polyamide 10K had Tg of 78° C., a melting point of 237° C., asemi-crystallization time of 27 seconds, an end amino groupconcentration of 39.1 μeq/g, an end carboxyl group concentration of 70.2μeq/g and a number average molecular weight of 17800. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 51.0 g/10 minutes.Further, a non-stretched film was prepared from the resulting polyamide10K alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 10K, and the mixturewas molten and kneaded with LLDPE in the same manners as in Example 4Kto produce an oxygen-absorbing multilayer film, and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

Comparative Example 4K

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 11K) was synthesized in the same manner as in Example4K, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.999:1 and that the polymerization time in the solid phasepolymerization was changed to 2 hours. The above polyamide 11K had Tg of78° C., a melting point of 237° C., a semi-crystallization time of 25seconds, an end amino group concentration of 34.8 μeq/g, an end carboxylgroup concentration of 58.6 μeq/g and a number average molecular weightof 21800. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 18.9 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 11K alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 11K, and the mixturewas molten and kneaded with LLDPE in the same manners as in Example 4Kto produce an oxygen-absorbing multilayer film, and the bag was chargedwith pineapple and subjected to heating treatment to measure an oxygenconcentration immediately after the heating treatment and a flavorthereof and a sealing strength of the bag after one month. The resultsthereof are shown in Table 2K.

The respective details of the polyamides 1K to 11K obtained above areshown in Table 1K, and the results of the respective examples andcomparative examples are shown in Table 2K.

TABLE 1K Oxygen End amino permeability group Solid MFR coefficient⁴⁾concentration phase End (g/10 (cc · mm/(m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ masking³⁾ minutes) day · atm))Polyamide 1K 17.5 MXDA Sebacic acid (0.4) ∘ x 11.0 0.34 (0.992) Adipicacid (0.6) (4 hours) (240° C.) Polyamide 2K 19.8 MXDA Adipic acid (1.0)∘ x 14.4 0.09 (0.991) (4 hours) (250° C.) Polyamide 3K 25.8 MXDA Adipicacid (1.0) x ∘ 29.8 0.13 (0.7) (260° C.) PXDA (0.3) Polyamide 4K 14.8MXDA Adipic acid (0.8) ∘ x 17.4 0.07 (0.991) Isophthalic acid (0.2) (4hours) (250° C.) Polyamide 5K 24.8 MXDA Sebacic acid (1.0) x x 65.4 1.58(0.994) (240° C.) Polyamide 6K 28.8 MXDA Adipic acid (0.95) ∘ x 10.10.08 (0.998) Isophthalic acid (0.05) (20 hours)  (240° C.) Polyamide 7K15.8 MXDA Sebacic acid (0.6) ∘ ∘ 11.4 0.74 (0.998) Adipic acid (0.4) (8hours) (240° C.) Polyamide 8K 19.5 MXDA Sebacic acid (0.3) ∘ x 10.5 0.21(0.992) Adipic acid (0.7) (4 hours) (240° C.) Polyamide 9K 19.2 MXDASebacic acid (0.7) ∘ x 10.1 0.68 (0.992) Adipic acid (0.3) (4 hours)(240° C.) Polyamide 10K 39.1 MXDA Adipic acid (1.0) x x 51.0 0.09(0.998) (250° C.) Polyamide 11K 34.8 MXDA Adipic acid (1.0) ∘ x 18.90.09 (0.999) (2 hours) (250° C.) MXDA: metaxylylenediamine, PXDA:paraxylylenediamine ¹⁾Numerical value in parentheses shows a mole ratioof each component. ²⁾∘: the solid phase polymerization was carried out.The polymerization time is shown in parentheses. x: the solid phasepolymerization was not carried out. ³⁾∘: the end amino group was masked.x: the end amino group was not masked. ⁴⁾A non-stretched film wasprepared from the polyamide alone, and an oxygen permeabilitycoefficient thereof was measured at 23° C. and 60% RH.

TABLE 2K Composition Polyamide (end amino Melting Film group kneadingOxygen Color Sealing concentration ratio¹⁾ Appearance concentrationTone²⁾ strength Example 1K Polyamide 1K 35:65 Good 0.6% 3 3.8 kg (17.5μeq/g) Example 2K Polyamide 1K 55:45 Good 2.0% 3 3.1 kg (17.5 μeq/g)Example 3K Polyamide 1K 25:75 Good 1.7% 3 3.7 kg (17.5 μeq/g) Example 4KPolyamide 2K 35:65 Good 5.5% 2 3.6 kg (19.8 μeq/g) Example 5K Polyamide3K 35:65 Slightly 5.1% 2 3.5 kg (25.8 μeq/g) inferior Example 6KPolyamide 4K 35:65 Good 4.1% 2 3.7 kg (14.8 μeq/g) Example 7K Polyamide5K 35:65 Slightly 9.3% 2 3.2 kg (24.8 μeq/g) inferior Example 8KPolyamide 6K 35:65 Good 3.8% 2 3.6 kg (28.8 μeq/g) Example 9K Polyamide7K 35:65 Good 0.5% 3 3.7 kg (15.8 μeq/g) Example 10K Polyamide 8K 35:65Good 2.4% 3 3.5 kg (19.5 μeq/g) Example 11K Polyamide 9K 35:65 Good 2.8%3 3.6 kg (19.2 μeq/g) Comparative Polyamide 1K 80:20 Good 12.8% 1 1.5 kgExample 1K (17.5 μeq/g) Comparative Polyamide 1K 10:90 Good 15.5% 1 3.6kg Example 2K (17.5 μeq/g) Comparative Polyamide 35:65 Inferior 14.6% 13.6 kg Example 3K 10K (39.1 μeq/g) Comparative Polyamide 35:65 Good13.9% 1 3.4 kg Example 4K 11K (34.8 μeq/g) ¹⁾(total weight of transitionmetal catalyst and polyamide resin): weight of polyolefin resin ²⁾Colortone 3: good, 2: Slightly good, 1: color tone lowered

As apparent from Examples 1K to 11K, the oxygen-absorbing resinmultilayer films of the present invention were multilayer films whichshowed a good oxygen-absorbing performance and maintained well a flavorof foods and which maintained a sealing strength of the films afterabsorbing oxygen.

In contrast with this, a sealing strength of the films was notablydeteriorated in Comparative Example 1K in which a content of thepolyamide A in the resin composition exceeded 60% by weight. Theoxygen-absorbing performance was unsatisfactory in Comparative Example2K in which a content of the polyamide A was less than 15% by weight. Inparticular, as apparent from comparison of Comparative Example 1K withExamples 1K to 3K, the good oxygen-absorbing performances were notnecessarily obtained when a content of the polyamide A in the resincomposition was large.

On the other hand, in Comparative Example 3K in which a mole ratio ofmetaxylylenediamine to adipic acid was increased and in which the solidphase polymerization was not carried out and Comparative Example 4K inwhich a mole ratio of metaxylylenediamine to adipic acid was increasedand in which the solid phase polymerization time was shortened, an endamino group concentration of the polyamide resins obtained exceeded 30μeq/g, and the good oxygen-absorbing performances were not obtained incomparison with Example 4K. Further, an appearance of the film wasdeteriorated as well in Comparative Example 3K.

Example 12K

Sila-ace S330 (3-aminopropyltriethoxysilane) 4.75 parts by weight whichwas a silane coupling agent manufactured by Chisso Corporation was addedto the coating liquid (epoxy resin composition) prepared in Example 1Kand stirred well to prepare a coating liquid (epoxy resin composition),and the coating liquid was anchor-coated in 2 μm on a silica-depositedpolyester film having 12 μm thickness (product name: “Tech Barrier L”manufactured by Mitsubishi Plastics, Inc.) and dried at 85° C. for 1second. Then, the two kind, three layer film 1 obtained in Example 1Kwas used and laminated thereon by extrusion lamination using low densitypolyethylene (product name: “Milason 18SP” manufactured by MitsuiChemicals, Inc.) to obtain an oxygen-absorbing multilayer film of asilica-deposited polyester film/epoxy resin-cured matter/low densitypolyethylene (20)/LLDPE (10)/oxygen-absorbing resin composition(20)/LLDPE (10). The above oxygen-absorbing multilayer film was chargedwith pickles of radish and subjected to heating treatment at 80° C., andthen it was stored at 23° C. to inspect a flavor thereof after 3 months.A flavor of the radish was confirmed to be maintained well.

Example 13K

An oxygen-absorbing resin composition was obtained in the same manner asin Example 1K, except that an ethylene-propylene block copolymer(product name: “Novatec FG3DC” manufactured by Japan PolypropyleneCorporation, MFR: 9.5 g/10 minutes at 230° C., MFR: 10.6 g/10 minutes at240° C., hereinafter referred to as PP) was used in place of LLDP. Then,a two kind, three layer film 2 (thickness: 15 μm/30 μm/15 μm) wasprepared in the same manner as in Example 1K, except that the aboveoxygen-absorbing resin composition was used for a core layer and that PPwas used for a skin layer in place of LLDPE. A HAZE of the film thusobtained was 24%.

Next, a methanol/ethyl acetate=9/1 solution (solid matter concentration:35% by weight) containing 22 parts by weight of an epoxy resin(TETRAD-X, manufactured by Mitsubishi Gas Chemicals, Inc.) having aglycidylamine part derived from metaxylylenediamine and 236 parts byweight of an epoxy resin curing agent a was prepared, and 0.4 part byweight of an acryl base wetting agent (BYK381, manufactured by BYKChemie A.G.) and 0.1 part by weight of a silicone base defoaming agent(BYK065, manufactured by BYK Chemie A.G.) were added thereto. Themixture was stirred well to obtain a coating liquid (epoxy resincomposition) in which an equivalent ratio (active hydrogen/epoxy group)of active hydrogen in the epoxy resin curing agent to an epoxy group inthe epoxy resin was 4.0. A content of the skeletal structure representedby Formula (1) in the epoxy resin-cured matter was 63.5% by weight.

The epoxy resin composition was coated in 8 μm on a corona-treatedsurface of the non-stretched polypropylene sheet 800 μm which wassubjected to corona discharge treatment and dried at 90° C. for 10seconds, and then the two kind, three layer film 2 was laminated thereonto obtain an oxygen-absorbing multilayer film. The multilayer film thusobtained was thermoformed into a cup (drawing ratio: 2.7) of 70 cc, andthe cup was charged with ground tea pudding and tightly sealed byheat-sealing using as a cover material, a film of aluminum-deposited PET(product name: “GL-AEH” manufactured by Toppan Printing Co., Ltd.,12)/adhesive (3)/nylon (product name: “N1202” manufactured by ToyoboCo., Ltd., 15)/adhesive (3)/PP (40). The tightly sealed cup wassubjected to heating treatment at 115° C. for 40 minutes and stored at23° C. for 3 months, and then a color tone of the ground tea pudding wasobserved. A color tone of the ground tea pudding was maintained well.

In the present invention, the specific polyamide resin and thetransition metal catalyst were blended with the polyolefin resin in aspecific proportion, and the specific epoxy resin-cured matter was usedfor lamination on an outer layer, whereby provided were theoxygen-absorbing multilayer films which were excellent in anoxygen-absorbing performance and maintained a resin strength afterstored and which were excellent in a processability and could be appliedto various containers and uses.

Example 1L

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.993:0.45:0.55 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1L). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 1L had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 16.8 μeq/g, an end carboxylgroup concentration of 92.0 μeq/g, a number average molecular weight of23700 and MFR of 11.0 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 1L alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.36cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1L through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 400 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1L) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with linear low density polyethylene(product name: “Kernel KF380” manufactured by Japan PolyethyleneCorporation, MFR: 4.0 g/10 minutes (measured according to JIS K7210),MFR: 8.7 g/10 minutes at 240° C., MFR: 10.0 g/10 minutes at 250° C.,hereinafter referred to as LLDPE) in a weight ratio of the cobaltstearate-containing polyamide 1L:LLDPE=35:65 to obtain anoxygen-absorbing resin composition.

A two kind, three layer film 1 (thickness: 10 μm/20 μm/10 μm) in whichthe oxygen-absorbing resin composition obtained was used for a corelayer and in which LLDPE was used for a skin layer was prepared bysubjecting one surface thereof to corona discharge treatment in a widthof 800 mm at 120 m/minute. An appearance of the film thus obtained wasgood. Layers were laminated on a corona-treated surface side of theabove film 1 by extrusion lamination using low density polyethylene(product name: “Milason 18SP” manufactured by Mitsui Chemicals, Inc.) toobtain an oxygen-absorbing multilayer paper substrate-laminated materialof bleached craft paper (basis weight: 330 g/m²)/urethane base adhesivefor dry laminate (product name: “TM251/CAT-RT88” manufactured byToyo-Morton, Ltd., 3)/aluminum-deposited PET film (product name:“GL-AEH” manufactured by Toppan Printing Co., Ltd., 12)/urethane baseanchor coating agent (product name: “EL-557A/B” manufactured byToyo-Morton, Ltd., 0.5)/low density polyethylene (20)/LLDPE(10)/oxygen-absorbing resin composition (20)/LLDPE (10). Numbers inparentheses mean a thickness (unit: μm) of the respective layers. Anoxygen-absorbing paper container 1 of a gable top type having a bottompart of 70 cm square and a capacity of 1000 mL was obtained from theabove laminated material. The paper container could be produced withoutcausing any problems on a processability thereof.

The above oxygen-absorbing paper container 1 was charged with 1000 mL ofwine so that an air amount of a head space was 20 cc, and it was storedat 35° C. to inspect a concentration of oxygen in the head space in the3rd day and a flavor of the wine after one month. Further, a thermallyfused strength in an upper part of the gable top type paper containerafter one month was measured.

Example 2L

An oxygen-absorbing paper container was produced in the same manner asin Example 1L, except that the weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1L:LLDPE=55:45.Then, a flavor of wine, a head space oxygen concentration and athermally fused strength in an upper part of the paper container wereinspected. The results thereof are shown in Table 2L.

Example 3L

An oxygen-absorbing paper container was produced in the same manner asin Example 1L, except that the weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1L:LLDPE 1=25:75.Then, a flavor of wine, a head space oxygen concentration and athermally fused strength in an upper part of the paper container wereinspected. The results thereof are shown in Table 2L.

Example 4L

Metaxylylenediamine and adipic acid were used in a mole ratio of 0.994:1and subjected to melt polymerization and solid phase polymerization onthe synthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide2L). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 4hours. The above polyamide 2L had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 19.6 μeq/g, an end carboxyl group concentration of 68.6μeq/g and a number average molecular weight of 23000. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 14.4 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 2L alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 2L, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1L,except that the temperature in melting and kneading was changed to 250°C.

Then, an oxygen-absorbing paper container was produced in the samemanner as in Example 1L, and a flavor of wine, a head space oxygenconcentration and a thermally fused strength in an upper part of thepaper container were inspected. The results thereof are shown in Table2L.

Example 5L

Metaxylylenediamine and paraxylylenediamine were mixed in 7:3, and theabove diamines and adipic acid were used in a mole proportion of 0.999:1and subjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 285° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 3L). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 277° C. and thereaction time to 30 minutes. The above polyamide 3L had Tg of 87° C., amelting point of 255° C., a semi-crystallization time of 18 seconds, anend amino group concentration of 25.8 μeq/g, an end carboxyl groupconcentration of 65.6 μeq/g and a number average molecular weight of18500. MFR could not be measured at 250° C. since it was close to themelting point, and MFR at 260° C. was measured to find that MFR at 260°C. was 29.8 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 3L alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 3L, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1L toproduce an oxygen-absorbing paper container, except that the temperaturein melting and kneading was changed to 265° C. Then, a flavor of wine, ahead space oxygen concentration and a thermally fused strength in anupper part of the paper container were inspected. The results thereofare shown in Table 2L.

Example 6L

Metaxylylenediamine, adipic acid and isophthalic acid were used in amole ratio of 0.992:0.8:0.2 and subjected to melt polymerization andsolid phase polymerization on the synthetic conditions described aboveto synthesize a polyamide resin (hereinafter, the above polyamide resinis referred to as the polyamide 4L). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 215°C. and the polymerization time to 4 hours. The above polyamide 4L had Tgof 92° C., a melting point of 230° C., a semi-crystallization time of250 seconds, an end amino group concentration of 14.9 μeq/g, an endcarboxyl group concentration of 67.5 μeq/g and a number averagemolecular weight of 23500. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 17.4 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 4L alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.07cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4L, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1L toproduce an oxygen-absorbing paper container, except that the temperaturein melting and kneading was changed to 250° C. Then, a flavor of wine, ahead space oxygen concentration and a thermally fused strength in anupper part of the paper container were inspected. The results thereofare shown in Table 2L.

Example 7L

Metaxylylenediamine and sebacic acid were used in a mole ratio of0.994:1 and subjected only to melt polymerization on the syntheticconditions described above to synthesize a polyamide resin (hereinafter,the above polyamide resin is referred to as the polyamide 5L).Controlled were the dropwise adding time to 2 hours and the reactiontime in the melt polymerization to 1 hour. The above polyamide 5L had Tgof 61° C., a melting point of 190° C., a semi-crystallization time of150 seconds, an end amino group concentration of 24.8 μeq/g, an endcarboxyl group concentration of 57.2 μeq/g, a number average molecularweight of 17200 and MFR of 65.4 g/10 minutes at 240° C. A non-stretchedfilm was prepared from the resulting polyamide 5L alone, and an oxygenpermeability coefficient thereof was determined to find that it was 1.58cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 5L, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 1L toproduce an oxygen-absorbing paper container. Then, a flavor of wine, ahead space oxygen concentration and a thermally fused strength in anupper part of the paper container were inspected. The results thereofare shown in Table 2L.

Comparative Example 1L

An oxygen-absorbing paper container was produced in the same manner asin Example 1L, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1L:LLDPE=80:20.Then, a flavor of wine, a head space oxygen concentration and athermally fused strength in an upper part of the paper container wereinspected. The results thereof are shown in Table 2L.

Comparative Example 2L

An oxygen-absorbing paper container was produced in the same manner asin Example 1L, except that the mixture was not molten and not kneadedwith LLDPE and that the film was prepared only from the cobaltstearate-containing polyamide 1L. Then, a flavor of wine, a head spaceoxygen concentration and a thermally fused strength in an upper part ofthe paper container were inspected. The results thereof are shown inTable 2L.

Comparative Example 3L

An oxygen-absorbing paper container was produced in the same manner asin Example 1L, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1L:LLDPE=10:90.Then, a flavor of wine, a head space oxygen concentration and athermally fused strength in an upper part of the paper container wereinspected. The results thereof are shown in Table 2L.

Comparative Example 4L

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 6L) was synthesized in the same manner as in Example4L, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.998:1 and not subjected to solid phase polymerization. Theabove polyamide 6L had Tg of 78° C., a melting point of 237° C., asemi-crystallization time of 27 seconds, an end amino groupconcentration of 39.1 μeq/g, an end carboxyl group concentration of 70.2μeq/g and a number average molecular weight of 17800. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 51.0 g/10 minutes.Further, a non-stretched film was prepared from the resulting polyamide6L alone, and an oxygen permeability coefficient thereof was determinedto find that it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6L, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 4L toproduce an oxygen-absorbing paper container. Then, a flavor of wine, ahead space oxygen concentration and a thermally fused strength in anupper part of the paper container were inspected. The results thereofare shown in Table 2L.

Comparative Example 5L

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 7L) was synthesized in the same manner as in Example4L, except that metaxylylenediamine and adipic acid were used in a moleratio of 0.999:1 and that a polymerization time in the solid phasepolymerization was changed to 2 hours. The above polyamide 7L had Tg of78° C., a melting point of 237° C., a semi-crystallization time of 25seconds, an end amino group concentration of 34.8 μeq/g, an end carboxylgroup concentration of 58.6 μeq/g and a number average molecular weightof 21800. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 18.9 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 7L alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 7L, and the mixture wasmolten and kneaded with LLDPE in the same manners as in Example 4L toproduce an oxygen-absorbing paper container. Then, a flavor of wine, ahead space oxygen concentration and a thermally fused strength in anupper part of the paper container were inspected. The results thereofare shown in Table 2L.

The respective details of the polyamides 1L to 7L obtained above areshown in Table 1L, and the results of the respective examples andcomparative examples are shown in Table 2L.

TABLE 1L Oxygen End amino permeability group Solid MFR coefficient⁴⁾concentration phase End (g/10 (cc · mm/(m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ masking³⁾ minutes) day · atm))Polyamide 1L 16.8 MXDA Sebacic acid (0.45) ∘ x 11.0 0.36 (0.993) Adipicacid (0.55) (4 hours) (240° C.) Polyamide 2L 19.6 MXDA Adipic acid (1.0)∘ x 14.4 0.09 (0.994) (4 hours) (250° C.) Polyamide 3L 25.8 MXDA +Adipic acid (1.0) x ∘ 29.8 0.13 PXDA⁵⁾ (260° C.) (0.999) Polyamide 4L14.9 MXDA Adipic acid (0.8) ∘ x 17.4 0.07 (0.992) Isophthalic acid (0.2)(4 hours) (250° C.) Polyamide 5L 24.8 MXDA Sebacic acid (1.0) x x 65.41.58 (0.994) (240° C.) Polyamide 6L 39.1 MXDA Adipic acid (1.0) x x 51.00.09 (0.998) (250° C.) Polyamide 7L 34.8 MXDA Adipic acid (1.0) ∘ x 18.80.09 (0.999) (2 hours) (250° C.) MXDA: metaxylylenediamine, PXDA:paraxylylenediamine ¹⁾Numerical value in parentheses shows a mole ratioof each component. ²⁾∘: the solid phase polymerization was carried out.The polymerization time is shown in parentheses. x: the solid phasepolymerization was not carried out. ³⁾∘: the end amino group was masked.x: the end amino group was not masked. ⁴⁾A non-stretched film wasprepared from the polyamide alone, and an oxygen permeabilitycoefficient thereof was measured at 23° C. and 60% RH. ⁵⁾Mixed ratio ofMXDA and PXDA MXDA:PXDA = 7:3

TABLE 2L Composition Polyamide (end amino Melting Oxygen Thermally groupkneading Fla- concen- fused concentration ratio¹⁾ vor tration strengthExample 1L Polyamide 1L 35 65 3 0.1% less 4.8 kg (16.8 μeq/g) Example 2LPolyamide 1K 55:45 3 0.2% 2.8 kg (16.8 μeq/g) Example 3L Polyamide 1L25:75 3 0.15% 4.2 kg (16.8 μeq/g) Example 4L Polyamide 2L 35:65 2 3.6%4.8 kg (19.6 μeq/g) Example 5 L Polyamide 3L 35:65 2 6.8% 4.6 kg (25.8μeq/g) Example 6L Polyamide 4L 35:65 2 2.4% 4.5 kg (14.9 μeq/g) Example7L Polyamide 5L 35:65 2 5.8% 4.5 kg (24.8 μeq/g) Comparative Polyamide1L 80:20 1 14.3% 1.2 kg Example 1L (16.8 μeq/g) Comparative Polyamide 1L100:0  1 15.5% 0.5 kg Example 2L (16.8 μeq/g) Comparative Polyamide 1L10:90 1 13.3% 4.5 kg Example 3L (16.8 μeq/g) Comparative Polyamide 6L35:65 1 10.5% 4.6 kg Example 4L (39.1 μeq/g) Comparative Polyamide 7L35:65 1 8.8% 4.6 kg Example 5L (34.8 μeq/g) ¹⁾(total weight oftransition metal catalyst and polyamide resin):weight of polyolefinresin ²⁾Flavor evaluation 3: flavor good, 2: flavor Slightly good, 1:flavor lowered

As apparent from Examples 1L to 7L, the oxygen-absorbing resincompositions of the present invention were resin compositions whichshowed an excellent oxygen-absorbing performance and a storing effect atany of a high humidity and a low humidity and which maintained acontainer strength after absorbing oxygen.

In contrast with this, the container strength was notably deterioratedin Comparative Examples 1L and 2L in which a content of the polyamide Ain the resin composition exceeded 60% by weight. Further, theoxygen-absorbing performances were unsatisfactory in Comparative Example2L in which the polyolefin resin was not added and Comparative Example3L in which a content of the polyamide A in the resin composition wasless than 20% by weight. In particular, as apparent from comparison ofComparative Examples 1L to 3L with Examples 1L to 3L, the goodoxygen-absorbing performances were not necessarily obtained when acontent of the polyamide A in the resin composition was large.

On the other hand, in Comparative Example 4L in which a mole ratio ofmetaxylylenediamine to adipic acid was increased as compared withExample 4L and in which the solid phase polymerization was not carriedout and Comparative Example 5L in which a mole ratio ofmetaxylylenediamine to adipic acid was increased and in which the solidphase polymerization time was shortened, an end amino groupconcentration of the polyamide resins obtained exceeded 30 μeq/g, andthe good oxygen-absorbing performances were not obtained.

Comparative Example 6L

Iron powder having an average particle diameter of 20 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith LLDPE in a weight ratio of 30:70 to obtain an iron powder baseoxygen-absorbing resin composition AL. A two kind, three layer film wastried to be prepared in the same manner as in Example 1L by using theiron powder base oxygen-absorbing resin composition AL for a core layer,but irregularities of the iron powder were generated on a film surface,and the film was not obtained. Accordingly, the iron powder baseoxygen-absorbing resin composition AL was extruded and laminated as anoxygen-absorbing layer in a thickness of 20 μm on LLDPE having athickness of 40 μm to obtain a laminated film which was subjected on anoxygen-absorbing layer surface to corona discharge treatment. The abovelaminated film was laminated on a bleached craft paper in the samemanner as in Example 1L to try to prepare a paper container of a gabletop type comprising an oxygen-absorbing multilayer paper base materialof bleached craft paper (basis weight: 300 g/m²)/urethane base adhesivefor dry laminate (product name: “TM251/CAT-RT88” manufactured byToyo-Morton, Ltd., 3)/aluminum-deposited PET film (product name:“GL-AEH” manufactured by Toppan Printing Co., Ltd., 12)/urethane baseanchor coating agent (product name: “EL-557A/B” manufactured byToyo-Morton, Ltd., 0.5)/low density polyethylene (product name: “Milason18SP” manufactured by Mitsui Chemicals, Inc., 20)/iron powder baseoxygen-absorbing resin composition AL (20)/LLDPE (40), but the thicknesswas large, and it was difficult to prepare a corner of the papercontainer. A preparing speed of the container was reduced to cut off therejected products, and the containers were obtained at last. A storingtest of wine was carried out in the same manner as in Example 1L, butaldehyde odor was generated in opening the container, and a flavorthereof was notably reduced.

In the present invention, the specific polyamide resin and thetransition metal catalyst were blended with the polyolefin resin in aspecific proportion, whereby provided were the oxygen-absorbing papercontainers which were excellent in an oxygen-absorbing performance andmaintained a container strength after stored and which were excellent ina processability.

Example 1M

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.991:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1M). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 1M had Tg of 72° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 17.2 μeq/g, an end carboxylgroup concentration of 86.3 μeq/g, a number average molecular weight of25000 and MFR of 10.4 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 1M alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.55cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide 1M through a side feed by means of a biaxial extrudingequipment so that a cobalt concentration was 200 ppm. Further, theresulting mixture (hereinafter referred to as the cobaltstearate-containing polyamide 1M) of the polyamide and cobalt stearatewas molten and kneaded at 240° C. with an ethylene-propylene randomcopolymer (product name: “PC630S” manufactured by SunAllomer Ltd., MFR:7.5 g/10 minutes at 230° C. (measured according to JIS K7210),hereinafter referred to as PP 1) as a polyolefin resin in a weight ratioof the cobalt stearate-containing polyamide 1M:PP 1=40:60 to obtain apellet comprising an oxygen-absorbing resin composition A.

A two lind, two layer film 1 (thickness: oxygen-absorbing layer 25μm/sealant layer 25 μm) in which the oxygen-absorbing resin compositionA obtained was used for an oxygen-absorbing layer and in which PP 1 wasused for a sealant layer was subjected on an oxygen-absorbing layersurface thereof to corona discharge treatment in a width of 800 mm at100 m/minute to prepare a film roll thereof. Uneven thickness such ashumps and the like was not observed on the film roll, and the filmobtained had a good appearance and a HAZE of 10%. A urethane baseadhesive for dry laminate (product name: “AD-817/CAT-RT86L-60”manufactured by Toyo-Morton, Ltd.) was used to laminate a nylon film(product name: “N1102” manufactured by Toyobo Co., Ltd.) andaluminum-deposited PET (product name: “GL-AEH” manufactured by ToyoboCo., Ltd.) on a corona-treated surface side to obtain anoxygen-absorbing multilayer film comprising an oxygen-absorbingmultilayer film of a nylon film (15)/adhesive (3)/aluminum-deposited PET(12)/adhesive (3)/oxygen-absorbing resin (25)/PP 1 (25).

Then, a three kind, five layer multilayer sheet-molding apparatuscomprising first to third extruding equipments, a feed block, a T die, acooling roll and a sheet receiving equipment was used to extrudecomponents from the respective extruding equipments to obtain agas-barriering multilayer sheet, wherein extruded were anethylene-propylene random copolymer (product name: “Novatec PP EG7F”manufactured by Japan Polypropylene Corporation, MFR: 1.3 g/10 minutes(measured according to JIS K7210), MFR: 8.2 g/10 minutes at 240° C.,MFR: 9.8 g/10 minutes at 250° C., hereinafter referred to as PP 2) fromthe first extruding equipment, MXD6 (product name: “MX Nylon S7007”manufactured by Mitsubishi Gas Chemical Company, Inc.) from the secondextruding equipment and maleic anhydride-modified polypropylene (productname: “Admer QF500” manufactured by Mitsui Chemicals, Inc., 15) from thethird extruding equipment. The constitution of the gas-barrieringmultilayer sheet was PP 2 (80)/maleic anhydride-modified polypropylene(product name: same as above, 15)/Nylon MXD6 (product name: same asabove, 40)/maleic anhydride-modified polypropylene (product name: sameas above, 15)/PP 2 (350) from the inner layer. The multilayer sheetprepared by co-extrusion was a multilayer sheet which was free fromthickness unevenness and the like and had a good appearance.

Next, the gas-barriering multilayer sheet thus obtained was subjected tothermoforming processing into a tray-like container (inner volume: 350cc, surface area: 200 cm²) (hereinafter referred to as a gas-barrieringmolded container 1) with the inner layer turned to an inside by means ofa vacuum molding machine. The gas-barriering molded container 1 obtainedwas free from thickness unevenness and had a good appearance. The abovecontainer was charged with 110 g of washed rice and 90 g of sterilizedwater, and an inside of the container was substituted with nitrogen toset an oxygen concentration to 10%. Then, the oxygen-absorbingmultilayer film was used as a cover material with a nylon film sideturned to an outer surface to tightly seal the container described aboveby heat sealing. The above container was put in a pressure heatingkettle and heated for cooking at 105° C. for 40 minutes, and aftercooled down, it was stored on the conditions of 23° C. and 50% RH. Aftercooled, the oxygen concentration was measured, and the kettle was openedafter 3 months since starting storing to confirm a flavor of the cookedrice and a strength of the gas-barriering container. The results thereofare shown in Table 2M.

Example 2M

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1M, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1M:PP 1=55:45. Then,the film was used as a cover material for the gas-barriering moldedcontainer 1 to carry out the same storing test as in Example 1M. Theresults thereof are shown in Table 2M.

Example 3M

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1M, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1M:PP 1=20:80. Then,the film was used as a cover material for the gas-barriering moldedcontainer 1 to carry out the same storing test as in Example 1M. Theresults thereof are shown in Table 2M.

Example 4M

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.993:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2M). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 2M had Tg of 79° C., amelting point of 190° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 18.3 μeq/g, an end carboxylgroup concentration of 80.3 μeq/g, a number average molecular weight of23500 and MFR of 11.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 2M alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.41cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1M so that a cobalt concentration was 200 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 2M)of the polyamide 2M and cobalt stearate was molten and kneaded with PP 1at 240° C. in a weight ratio of the cobalt stearate-containing polyamide2M:PP 1=40:60 to obtain an oxygen-absorbing resin pellet. Further, anoxygen-absorbing multilayer film was obtained in the same manner as inExample 1M, and then the film was used as a cover material for thegas-barriering molded container 1 to carry out the same storing test asin Example 1M. The results thereof are shown in Table 2M.

Example 5M

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.992:0.6:0.4 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 3M). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 3M had Tg of 77° C., amelting point of 189° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 15.6 μeq/g, an end carboxylgroup concentration of 81.2 μeq/g, a number average molecular weight of24500 and MFR of 10.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 3M alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.24cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1M so that a cobalt concentration was 200 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 3M)of the polyamide 3M and cobalt stearate was molten and kneaded with PP 1at 240° C. in a weight ratio of the cobalt stearate-containing polyamide3M:PP 1=40:60 to obtain an oxygen-absorbing resin pellet. Further, anoxygen-absorbing multilayer film was obtained in the same manner as inExample 1M, and then the film was used as a cover material for thegas-barriering molded container 1 to carry out the same storing test asin Example 1M. The results thereof are shown in Table 2M.

Example 6M

Metaxylylenediamine and paraxylylenediamine were mixed in 7:3, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 270° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 4M). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 270° C. and thereaction time to 30 minutes. The above polyamide 4M had Tg of 85° C., amelting point of 255° C., a semi-crystallization time of 22 seconds, anend amino group concentration of 24.7 μeq/g, an end carboxyl groupconcentration of 60.2 μeq/g and a number average molecular weight of18400. MFR could not be measured at 260° C. since it was close to themelting point, and MFR at 270° C. was measured to find that MFR at 270°C. was 33.4 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 4M alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.08 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 4M, and the mixture wasmolten and kneaded with PP 1 in the same manner as in Example 1M, exceptthat the temperature in melting and kneading was changed to 270° C.Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1M, and then the film was used as a cover materialfor the gas-barriering molded container 1 to carry out the same storingtest as in Example 1M. The results thereof are shown in Table 2M.

Example 7M

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.994:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 5M). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 4 hours. The polyamide 5M had Tg of 73° C., amelting point of 185° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 17.6 μeq/g, an end carboxylgroup concentration of 77.3 μeq/g, a number average molecular weight of22900 and MFR of 13.6 g/10 minutes at 240° C. A non-stretched film wasprepared from the resulting polyamide 5M alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.69cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 5M, and the mixture wasmolten and kneaded with PP 1 in the same manners as in Example 1M.Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1M, and then the film was used as a cover materialfor the gas-barriering molded container 1 to carry out the same storingtest as in Example 1M. The results thereof are shown in Table 2M.

Example 8M

Metaxylylenediamine and adipic acid were used in a mole ratio of 0.991:1and subjected to melt polymerization and solid phase polymerization onthe synthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide6M). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 4hours. The above polyamide 6M had Tg of 84° C., a melting point of 239°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 19.1 μeq/g, an end carboxyl group concentration of 87.0μeq/g and a number average molecular weight of 23000. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 13.8 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 4M alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6M, and the mixture wasmolten and kneaded with PP 1 in the same manners as in Example 1M,except that the temperature in melting and kneading was changed to 250°C. Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1M, and then the film was used as a cover materialfor the gas-barriering molded container 1 to carry out the same storingtest as in Example 1M. The results thereof are shown in Table 2M.

Comparative Example 1M

A film was produced in the same manner as in Example 1M, except that aweight ratio in melting and kneading was changed to the cobaltstearate-containing polyamide 1M:PP 1=85:15. Then, the film was used asa cover material for the gas-barriering molded container 1 to carry outthe same storing test as in Example 1M. The results thereof are shown inTable 2M.

Comparative Example 2M

A film was produced in the same manner as in Example 1M, except that themixture was not molten and not kneaded with PP 1 and that theoxygen-absorbing layer was prepared only from the cobaltstearate-containing polyamide 1M. Then, the film was used as a covermaterial for the gas-barriering molded container 1 to carry out the samestoring test as in Example 1M. The results thereof are shown in Table2M.

Comparative Example 3M

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 7M) was synthesized in the same manner as in Example4M, except that metaxylylenediamine:sebacic acid:adipic acid were usedin a mole ratio of 1.0:0.3:0.7 and not subjected to solid phasepolymerization. The above polyamide 7M had Tg of 76° C., a melting pointof 185° C., a semi-crystallization time of 2000 seconds or longer, anend amino group concentration of 35.1 μeq/g, an end carboxyl groupconcentration of 60.2 μeq/g and a number average molecular weight of17000. MFR at 240° C. was 60.0 g/10 minutes. Further, a non-stretchedfilm was prepared from the resulting polyamide 7M alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.44cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 7M, and the mixture wasmolten and kneaded with PP 1 in the same manners as in Example 1M toproduce a film in the same manner as in Example 1M, and then the filmwas used as a cover material for the gas-barriering molded container 1to carry out the same storing test as in Example 1M. The results thereofare shown in Table 2M.

Comparative Example 4M

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide resin 8M) was synthesized in the same manner as inExample 8M, except that metaxylylenediamine:adipic acid were used in amole ratio of 0.997:1 and that the polymerization time in the solidphase polymerization was changed to 2 hours. The above polyamide resin8M had Tg of 73° C., a melting point of 232° C., a semi-crystallizationtime of 25 seconds, an end amino group concentration of 38.3 μeq/g, anend carboxyl group concentration of 58.6 μeq/g and a number averagemolecular weight of 21800. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 19.5 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 8M alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.09cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 8M, and the mixture wasmolten and kneaded with PP 1 in the same manners as in Example 1M toobtain an oxygen-absorbing resin pellet, except that the temperature inmelting and kneading was changed to 250° C. Further, an oxygen-absorbingmultilayer film was obtained in the same manner as in Example 1M, andthen the film was used as a cover material for the gas-barriering moldedcontainer 1 to carry out the same storing test as in Example 1M. Theresults thereof are shown in Table 2M.

The respective details of the polyamides 1M to 8M obtained above areshown in Table 1M, and the results of the respective examples andcomparative examples are shown in Table 2M.

TABLE 1M Oxygen End amino permeability group Solid MFR Coefficient⁴⁾concentration phase End (g/10 (cc · mm/(m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ masLing³⁾ minutes) day · atm))Polyamide 1M 17.2 MXDA Sebacic acid (0.7) ∘ x 10.4 0.55 (0.991) Adipicacid (0.3) (4 hours) (240° C.) Polyamide 2M 18.3 MXDA Sebacic acid (0.3)∘ x 11.1 0.41 (0.993) Adipic acid (0.7) (4 hours) (240° C.) Polyamide 3M15.6 MXDA Sebacic acid (0.6) ∘ x 10.1 0.24 (0.992) Adipic acid (0.4) (4hours) (240° C.) Polyamide 4M 24.7 MXDA Adipic acid (1.0) x ∘ 33.4 0.08(0.7) (270° C.) PXDA (0.3) Polyamide 5M 17.6 MXDA Sebacic acid (0.4) ∘ x13.6 0.69 (0.994) Adipic acid (0.6) (4 hours) (240° C.) Polyamide 6M19.1 MXDA Adipic acid (1.0) ∘ x 13.8 0.09 (0.991) (4 hours) (250° C.)Polyamide 7M 35.1 MXDA Sebacic acid (0.3) x x 60.0 0.44 (1.0) Adipicacid (0.7) (240° C.) Polyamide 8M 38.3 MXDA Adipic acid (1.0) ∘ x 19.50.09 (0.997) (2 hours) (250° C.) MXDA: metaxylylenediamine, PXDA:paraxylylenediamine ¹⁾Numerical value in parentheses shows a mole ratioof each component. ²⁾∘: the solid phase polymerization was carried out.The polymerization time is shown in parentheses. x: the solid phasepolymerization was not carried out. ³⁾∘: the end amino group was masked.x: the end amino group was not masked. ⁴⁾A non-stretched film wasprepared from the polyamide alone, and an oxygen permeabilitycoefficient thereof was measured at 23° C. and 60% RH.

TABLE 2M Composition Concentration Flavor of Polyamide Appearance ofoxygen cooked (end amino Melting of after heating rice after groupkneading film for cooking stored for concentration ratio¹⁾ roll andcooling 3 months Example 1M Polyamide 1M 40:60 Good 0.7% Good (17.2μeq/g) Example 2M Polyamide 1M 55:45 Slightly 1.5% Almost good (17.2μeq/g) inferior Example 3M Polyamide 1M 20:80 Good 1.7% Almost good(17.2 μeq/g) Example 4M Polyamide 2M 40:60 Good 1.7% Almost good (18.3q/g) Example 5M Polyamide 3M 40:60 Good 0.9% Good (15.6 μeq/g) Example6M Polyamide 4M 40:60 Slightly 2.3% Slightly (24.7 μeq/g) inferiorinferior Example 7M Polyamide 5M 40:60 Good 0.6% Good (17.6 μeq/g)Example 8M Polyamide 6M 40:60 Good 1.5% Almost good (19.1 μeq/g)Comparative Polyamide 1M 85:15 Slightly 7.1% Lowered Example 1M (17.2μeq/g) inferior Comparative Polyamide 1M 100:0  Good 7.7% LoweredExample 2M (17.2 μeq/g) Comparative Polyamide 7M 40:60 Slightly 6.1%Lowered Example 3M (35.1 μeq/g) inferior Comparative Polyamide 8M 40:60Slightly 6.5% Lowered Example 4M (38.3 μeq/g) inferior ¹⁾(total weightof transition metal catalyst and polyamide resin):weight of polyolefinresin

Example 9M

A pellet comprising an oxygen-absorbing resin composition B was obtainedin the same manner as in Example 1M, except that an ethylene-propylenerandom copolymer (product name: “Novatec PP FW4BT” manufactured by JapanPolypropylene Corporation, MFR: 6.5 g/10 minutes at 230° C. (measuredaccording to JIS K7210), hereinafter referred to as PP 3) was used inplace of PP 1. A two kind, two layer film 2 was prepared in the samemanner as in Example 1M by using the resulting oxygen-absorbing resincomposition B for an oxygen-absorbing layer and using PP 3 for a sealantlayer. The film obtained has a good appearance and a HAZE of 13%.Subsequently, an ethylene-vinyl alcohol copolymer film (product name:“Eval EF-XL” manufactured by Kuraray Co., Ltd.) 15 μm and a nylon film(product name: “N1102” manufactured by Toyobo Co., Ltd) 15 μm werelaminated thereon by using an adhesive for lamination to obtain anoxygen-absorbing multilayer film of a nylon film (15)/adhesive forlamination (3)/ethylene vinyl alcohol copolymer film (15)/adhesive forlamination (3)/oxygen-absorbing resin (30)/PP 3 (30). An appearance ofthe film was good.

Then, a three kind, five layer multilayer sheet-molding apparatuscomprising first to third extruding equipments, a feed block, a T die, acooling roll and a sheet receiving equipment was used to extrudecomponents from the respective extruding equipments to obtain agas-barriering multilayer sheet, wherein extruded were anethylene-propylene random copolymer (product name: “Novatec PP EG6D”manufactured by Japan Polypropylene Corporation, MFR: 1.9 g/10 minutes(measured according to JIS K7210), hereinafter referred to as PP 4) fromthe first extruding equipment, an ethylene-vinyl alcohol copolymer film(product name: “Eval L171B” manufactured by Kuraray Co., Ltd., 40) fromthe second extruding equipment and maleic anhydride-modifiedpolypropylene (product name: “Modec AP P604” manufactured by MitsubishiChemical Corporation) from the third extruding equipment. Theconstitution of the gas-barriering multilayer sheet was PP 4(400)/maleic anhydride-modified polypropylene (product name: same asabove, 15)/ethylene-vinyl alcohol copolymer (product name: same asabove, 40)/maleic anhydride-modified polypropylene (product name: sameas above, 15)/PP 4 (400) from the inner layer. The multilayer sheetprepared by co-extrusion was a multilayer sheet which was free fromthickness unevenness and the like and had a good appearance.

Next, the gas-barriering multilayer sheet thus obtained was molded intoa cup of 80 cc at a drawing ratio of 2.5 (hereinafter referred to as thegas-barriering molded container 2), and the gas-barriering moldedcontainer 2 was fully charged with an apple jelly and tightly sealed byheat sealing using the prepared oxygen-absorbing multilayer film as acover material with a nylon film layer side turned to an outer face. Acolor tone of the content could be visually confirmed through the covermaterial. The tightly sealed container was subjected to heatingtreatment at 85° C. for 30 minutes and then stored at 23° C. for onemonth. After one month, the container was opened to find that an openingproperty thereof was good without being turned into a double cap andthat a flavor and a color tone of the content were maintained well.

Comparative Example 5M

Iron powder 150 kg having an average particle diameter of 30 μm was putin a vacuum dryer equipped with a heating jacket, and a calcium chloride50 weight % aqueous solution 70 kg was sprayed thereon while mixing themat 150° C. under reduced pressure of 10 mm Hg to dry the mixture. Then,the mixture was sieved to remove coarse particles, and an iron baseoxygen-absorbing agent 1 having an average particle diameter of 30 μmwas obtained. Next, the iron base oxygen-absorbing agent and calciumoxide were supplied trough a side feed by means of a biaxial extrudingequipment equipped with a bent while extruding PP 3, and the mixture waskneaded so that a weight ratio of PP 3:iron base oxygen-absorbing agent1: calcium oxide was 58:40:2 to obtain a pellet comprising anoxygen-absorbing resin composition C.

An oxygen-absorbing multilayer film and a gas-barriering moldedcontainer 2 were produced in the same manners as in Example 9M, exceptthat the resin used for the oxygen-absorbing layer was changed to theoxygen-absorbing resin composition C, and then the oxygen-absorbing filmwas used as a cover material to carry out the same storing test as inExample 9M. As result thereof, a flavor and a color tone of the contentwere maintained well, but in opening the oxygen-absorbing film of thecover material, it could not be opened well. A part of theoxygen-absorbing layer of the oxygen-absorbing film used for the covermaterial was broken, and the iron powder remained and was adhered onto aflange of the gas-barriering molded container 2, so that an appearancethereof was damaged.

The present invention related to the oxygen-absorbing sealing containerprepared by using as a cover material for the oxygen-absorbing film, theoxygen-absorbing multilayer film which was excellent in anoxygen-absorbing performance at a low humidity and a high humidity andmaintained a resin strength after stored and which was excellent in aprocessability by blending the specific polyamide resin and thetransition metal catalyst with the polyolefin resin in a specificproportion.

Method for Storing a Content of an Infusion Container Example 1N

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.994:0.4:0.6 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 1N). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 6 hours. The polyamide 1N had Tg of 73° C., amelting point of 184° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 14.8 μeq/g, an end carboxylgroup concentration of 63.4 μeq/g, a number average molecular weight of25600 and MFR of 10.3 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 1N alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.34cc·mm/(m²·day·atm) (23° C., 60% RH).

Cobalt stearate was added as a transition metal catalyst to the moltenpolyamide through a side feed by means of a biaxial extruding equipmentso that a cobalt concentration was 400 ppm. Further, the resultingmixture (hereinafter referred to as the cobalt stearate-containingpolyamide 1N) of the polyamide and cobalt stearate was molten andkneaded at 240° C. with an ethylene-propylene block copolymer (productname: “Novatec PP BC3HF” manufactured by Japan PolypropyleneCorporation, MFR: 8.5 g/10 minutes at 230° C., MFR: 10.8 g/10 minutes at240° C., MFR: 12.1 g/10 minutes at 250° C., hereinafter referred to asPP) in a weight ratio of the cobalt stearate-containing polyamide1N:PP=35:65 to obtain a pellet comprising an oxygen-absorbing resincomposition A.

A two kind, three layer film (thickness: intermediate layer 20μm/oxygen-absorbing resin layer 20 μm/oxygen-permeating layer 20 μm) inwhich the oxygen-absorbing resin composition obtained was used for anoxygen-absorbing resin layer and in which PP was used for anoxygen-permeating layer and an intermediate layer was subjected on anintermediate layer surface thereof to corona discharge treatment in awidth of 700 mm at 30 m/minute to prepare a film roll thereof. Uneventhickness such as humps and the like was not observed on the film roll,and the film obtained had a good appearance and a HAZE of 85%. Aurethane base adhesive for dry laminate (product name:“AD-817/CAT-RT86L-60” manufactured by Toyo-Morton, Ltd.) was used tolaminate a PET film (product name: “E5100” manufactured by Toyobo Co.,Ltd.) and an aluminum-deposited PET film (product name: “GL-AU”manufactured by Toppan Printing Co., Ltd.) on a corona-treated surfaceside hereof to obtain an oxygen-absorbing multilayer film of a PET film(12)/adhesive (3)/aluminum-deposited PET film (12)/adhesive (3)/PP(20)/oxygen-absorbing resin (20)/PP (20). Numbers in parentheses mean athickness (unit: μm) of the respective layers. Next, a three side-sealedbag of 15 cm×30 cm was prepared with an oxygen-permeating layer sideturned to an inner face. The bag was charged under nitrogen substitutionwith a polypropylene-made bottle in which tightly sealed was 200 ml ofan amino acid preparation model liquid prepared by dissolving L-leucine,L-isoleucine, lysine acetate, L-methionine, L-phenylalanine,L-threonine, L-tryptophan, L-valine, L-arginine, L-histidine, L-alanineand glucose in water. A nitrogen substitution rate in the bag was 90%.Then, the bag was stored at 40° C. and 90% RH, and an oxygenconcentration in the bag after 1 month and 3 months and a color changein the polypropylene-made bottle were inspected from an outside of thebag. Further, the sealing strength after stored for 3 months wasmeasured. The results thereof are shown in Table 2N.

Example 2N

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1N, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1N:PP=55:45. Then, athree side-sealed bag was prepared to carry out the same storing test asin Example 1N. The results thereof are shown in Table 2N.

Example 3N

An oxygen-absorbing multilayer film was obtained in the same manner asin Example 1N, except that a weight ratio in melting and kneading waschanged to the cobalt stearate-containing polyamide 1N:PP=20:80. Then, athree side-sealed bag was prepared to carry out the same storing test asin Example 1N. The results thereof are shown in Table 2N.

Example 4N

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.994:0.7:0.3 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 2N). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 6 hours. The polyamide 2N had Tg of 65° C., amelting point of 170° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 15.7 μeq/g, an end carboxylgroup concentration of 61.5 μeq/g, a number average molecular weight of25900 and MFR of 10.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 2N alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0:68cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1N so that a cobalt concentration was 400 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 2N)of the polyamide 2N and cobalt stearate was molten and kneaded with PPat 240° C. in a weight ratio of the cobalt stearate-containing polyamide2N:PP=35:65 to obtain an oxygen-absorbing resin pellet. Further, anoxygen-absorbing multilayer film was obtained in the same manner as inExample 1N, and then a three side-sealed bag was prepared to carry outthe same storing test as in Example 1N. The results thereof are shown inTable 2N.

Example 5N

Metaxylylenediamine:sebacic acid:adipic acid were used in a mole ratioof 0.994:0.3:0.7 and subjected to melt polymerization and solid phasepolymerization on the synthetic conditions described above to synthesizea polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide 3N). Controlled were the dropwise adding time to 2hours, the reaction time in the melt polymerization to 1 hour, thepressure in an inside of the equipment in the solid phase polymerizationto 1 torr or less, the polymerization temperature to 160° C. and thepolymerization time to 6 hours. The polyamide 3N had Tg of 78° C., amelting point of 194° C., a semi-crystallization time of 2000 seconds orlonger, an end amino group concentration of 16.1 μeq/g, an end carboxylgroup concentration of 64.7 μeq/g, a number average molecular weight of24800 and MFR of 11.1 g/10 minutes at 240° C. Further, a non-stretchedfilm was prepared from the resulting polyamide 3N alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.21cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added thereto in the same manner as in Example1N so that a cobalt concentration was 400 ppm, and the resulting mixture(hereinafter referred to as the cobalt stearate-containing polyamide 3N)of the polyamide 3N and cobalt stearate was molten and kneaded with PPat 240° C. in a weight ratio of the cobalt stearate-containing polyamide3N:PP=35:65 to obtain an oxygen-absorbing resin pellet. Further, anoxygen-absorbing multilayer film was obtained in the same manner as inExample 1N, and then a three side-sealed bag was prepared to carry outthe same storing test as in Example 1N. The results thereof are shown inTable 2N.

Example 6N

Metaxylylenediamine:adipic acid were used in a mole ratio of 0.994:1 andsubjected to melt polymerization and solid phase polymerization on thesynthetic conditions described above to synthesize a polyamide resin(hereinafter, the above polyamide resin is referred to as the polyamide4N). Controlled were the dropwise adding time to 2 hours, the reactiontime in the melt polymerization to 1 hour, the pressure in an inside ofthe equipment in the solid phase polymerization to 1 torr or less, thepolymerization temperature to 205° C. and the polymerization time to 6hours. The above polyamide 4N had Tg of 84° C., a melting point of 237°C., a semi-crystallization time of 25 seconds, an end amino groupconcentration of 13.9 μeq/g, an end carboxyl group concentration of 65.5μeq/g and a number average molecular weight of 25200. MFR could not bemeasured at 240° C. since it was close to the melting point, and MFR at250° C. was measured to find that MFR at 250° C. was 12.2 g/10 minutes.A non-stretched film was prepared from the resulting polyamide 4N alone,and an oxygen permeability coefficient thereof was determined to findthat it was 0.09 cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 4N, and the mixture wasmolten and kneaded with PP in the same manners as in Example 1N, exceptthat the temperature in melting and kneading was changed to 250° C.Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1N, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1N. The results thereofare shown in Table 2N.

Example 7N

Metaxylylenediamine and paraxylylenediamine were mixed in 8:2, and theabove diamines and adipic acid were used in a mole proportion of 1:1 andsubjected only to melt polymerization on the synthetic conditionsdescribed above to synthesize a polyamide resin. Then, phthalicanhydride 0.2 wt % was added thereto, and the mixture was molten andkneaded at 270° C. by means of a biaxial extruding equipment to mask anend amino group (hereinafter, the above polyamide resin is referred toas the polyamide 5N). Controlled were the dropwise adding time to 2hours, the polymerization temperature after finishing dropwise addingmetaxylylenediamine in the melt polymerization to 270° C. and thereaction time to 30 minutes. The above polyamide 5N had Tg of 85° C., amelting point of 255° C., a semi-crystallization time of 24 seconds, anend amino group concentration of 24.4 μeq/g, an end carboxyl groupconcentration of 60.2 μeq/g and a number average molecular weight of19000. MFR could not be measured at 260° C. since it was close to themelting point, and MFR at 270° C. was measured to find that MFR at 270°C. was 33.1 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 5N alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.13 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 5N, and the mixture wasmolten and kneaded with PP in the same manners as in Example 1N, exceptthat the temperature in melting and kneading was changed to 270° C.Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1N, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1N. The results thereofare shown in Table 2N.

Example 8N

Metaxylylenediamine:adipic acid:isophthalic acid were used in a moleratio of 0.991:0.9:0.1 and subjected to melt polymerization and solidphase polymerization on the synthetic conditions described above tosynthesize a polyamide resin (hereinafter, the above polyamide resin isreferred to as the polyamide 6N). Controlled were the dropwise addingtime to 2 hours, the reaction time in the melt polymerization to 1 hour,the pressure in an inside of the equipment in the solid phasepolymerization to 1 torr or less, the polymerization temperature to 205°C. and the polymerization time to 6 hours. The above polyamide 6N had Tgof 94° C., a melting point of 228° C., a semi-crystallization time of300 seconds, an end amino group concentration of 17.5 μeq/g, an endcarboxyl group concentration of 63.7 μeq/g and a number averagemolecular weight of 24600. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 13.6 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 6N alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.08cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 6N, and the mixture wasmolten and kneaded with PP in the same manners as in Example 1N, exceptthat the temperature in melting and kneading was changed to 250° C.Further, an oxygen-absorbing multilayer film was obtained in the samemanner as in Example 1N, and then a three side-sealed bag was preparedto carry out the same storing test as in Example 1N. The results thereofare shown in Table 2N.

Comparative Example 1N

A film was produced in the same manner as in Example 1N, except that aweight ratio in melting and kneading was changed to the cobaltstearate-containing polyamide 1N:PP=85:15. Then, a three side-sealed bagwas prepared to carry out the same storing test as in Example 1N. Theresults thereof are shown in Table 2N.

Comparative Example 2N

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide resin 7N) was synthesized in the same manner as inExample 6N, except that metaxylylenediamine:adipic acid were used in amole ratio of 1:1. The above polyamide resin 7N had Tg of 84° C., amelting point of 237° C., a semi-crystallization time of 25 seconds, anend amino group concentration of 40.5 μeq/g, an end carboxyl groupconcentration of 42.2 μeq/g and a number average molecular weight of24200. MFR could not be measured at 240° C. since it was close to themelting point, and MFR at 250° C. was measured to find that MFR at 250°C. was 13.1 g/10 minutes. A non-stretched film was prepared from theresulting polyamide 7N alone, and an oxygen permeability coefficientthereof was determined to find that it was 0.09 cc·mm/(m²·day·atm) (23°C., 60% RH).

Then, cobalt stearate was added to the polyamide 7N, and the mixture wasmolten and kneaded with PP in the same manners as in Example 6N toproduce a film in the same manner as in Example 1N. Then, a threeside-sealed bag was prepared to carry out the same storing test as inExample 1N. The results thereof are shown in Table 2N.

Comparative Example 3N

A polyamide resin (hereinafter, the above polyamide resin is referred toas the polyamide resin 8N) was synthesized in the same manner as inExample 6N, except that metaxylylenediamine:adipic acid were used in amole ratio of 0.994:1 and that the polymerization time in the solidphase polymerization was changed to 1 hour. The above polyamide resin 8Nhad Tg of 84° C., a melting point of 237° C., a semi-crystallizationtime of 25 seconds, an end amino group concentration of 32.9 μeq/g, anend carboxyl group concentration of 83.1 μeq/g and a number averagemolecular weight of 17200. MFR could not be measured at 240° C. since itwas close to the melting point, and MFR at 250° C. was measured to findthat MFR at 250° C. was 40.2 g/10 minutes. A non-stretched film wasprepared from the resulting polyamide 8N alone, and an oxygenpermeability coefficient thereof was determined to find that it was 0.09cc·mm/(m²·day·atm) (23° C., 60% RH).

Then, cobalt stearate was added to the polyamide 8N, and the mixture wasmolten and kneaded with PP in the same manners as in Example 6N toproduce a film in the same manner as in Example 1N. Then, a threeside-sealed bag was prepared to carry out the same storing test as inExample 1N. The results thereof are shown in Table 2N.

The respective details of the polyamides 1N to 8N obtained above areshown in Table 1N, and the results of the respective examples andcomparative examples are shown in Table 2N.

TABLE 1N Oxygen End amino permeability group Solid MFR Coefficient⁴⁾concentration phase End (g/10 (cc · mm/m² · (μeq/g) Diamine¹⁾Dicarboxylic acid¹⁾ polymerization²⁾ masLing³⁾ minutes) day · atm))Polyamide 1N 14.8 MXDA Sebacic acid (0.4) Present (6 None 10.3 0.34(0.994) Adipic acid (0.6) hours) (240° C.) Polyamide 2N 15.7 MXDASebacic acid (0.7) Present (6 None 10.1 0.68 (0.994) Adipic acid (0.3)hours) (240° C.) Polyamide 3N 16.1 MXDA Sebacic acid (0.3) Present (6None 11.1 0.21 (0.994) Adipic acid (0.7) hours) (240° C.) Polyamide 4N13.9 MXDA Adipic acid (1.0) Present (6 None 12.2 0.09 (0.994) hours)(250° C.) Polyamide 5N 24.4 MXDA Adipic acid (1.0) None Present 33.10.13 (0.8) (270° C.) PXDA (0.2) Polyamide 6N 17.5 MXDA Adipic acid (0.9)Present (6 None 13.6 0.08 (0.991) Isophthalic acid (0.1) hours) (250°C.) Polyamide 7N 40.5 MXDA Adipic acid (1.0) Present (6 None 13.1 0.09(1.0) hours) (250° C.) Polyamide 8N 32.9 MXDA Adipic acid (1.0) Present(1 None 40.2 0.09 (0.994) hour) (250° C.) MXDA: metaxylylenediamine,PXDA: paraxylylenediamine ¹⁾Numerical value in parentheses shows a moleratio of each component. ²⁾Present: the solid phase polymerization wascarried out. The polymerization time is shown in parentheses. None: thesolid phase polymerization was not carried out. ³⁾Present: the end aminogroup was masked. None: the end amino group was not masked. ⁴⁾Anon-stretched film was prepared from the polyamide alone, and an oxygenpermeability coefficient thereof was measured at 23° C. and 60% RH.

TABLE 2N Composition Sealing Polyamide strength (end amino MeltingStored for 1 month Stored for 3 months after group kneading OxygenOxygen stored for concentration ratio¹⁾ concentration Appearanceconcentration Appearance 3 months Example 1N Polyamide 1N 35:65 3.3% Nochange 0.1% No change 4.6 kg/15 mm (14.8 μeq/g) or less Example 2NPolyamide 1N 55:45 4.1% No change 0.6% No change 3.3 kg/15 mm (14.8μeq/g) Example 3N Polyamide 1N 20:80 3.8% No change 0.4% No change 5.2kg/15 mm (14.8 μeq/g) Example 4N Polyamide 2N 35:65 3.9% No change 0.4%No change 4.4 kg/15 mm (15.7 μeq/g) Example 5N Polyamide 3N 35:65 4.2%No change 0.8% No change 4.3 kg /15 mm (16.1 μeq/g) Example 6N Polyamide4N 35:65 4.5% No change 1.0% Faint 4.5 kg/15 mm (13.9 μeq/g) brownExample 7N Polyamide 5N 35:65 5.1% No change 1.5% Faint 4.5 kg/15 mm(24.4 μeq/g) brown Example 8N Polyamide 6N 35:65 3.8% No change 0.3%Faint 4.4 kg/15 mm (17.5 μeq/g) brown Comparative Polyamide 1N 85:157.3% Faint 3.1% Faint 1.0 kg/15 mm Example 1N (14.8 μeq/g) brown brownComparative Polyamide 7N 35:65 8.1% Faint 6.5% Brown 4.6 kg/15 mmExample 2N (40.5 μeq/g) brown Comparative Polyamide 8N 35:65 7.9% Faint5.9% Brown 4.7 kg/15 mm Example 3N (32.9 μeq/g) brown ¹⁾(total weight oftransition metal catalyst and polyamide resin):weight of polyolefinresin

As apparent from Examples 1N to 8N, the oxygen-absorbing resincompositions of the present invention were excellent in anoxygen-absorbing performance and reduced in an oxygen concentration inthe bag, and they maintained a color tone of the contents and weresuited to storage of a content in the infusion container.

In contrast with this, in Comparative Example 1N in which a content ofthe polyamide A in the oxygen-absorbing resin layer exceeded 60% byweight, the oxygen-absorbing performance was unsatisfactory, and thecontent was discolored.

On the other hand, in Comparative Example 2N in which a mole ratio ofmetaxylylenediamine to adipic acid was increased as compared withExample 6N and Comparative Example 3N in which the solid phasepolymerization time was shortened, the end amino group concentrationsexceeded 30 μeq/g, and the oxygen-absorbing performances wereunsatisfactory. Further, the contents were discolored.

Comparative Example 4N

Iron powder having an average particle diameter of 30 μm was mixed withcalcium chloride in a proportion of 100:1, and the mixture was kneadedwith PP in a weight ratio of 30:70 to obtain an iron baseoxygen-absorbing resin composition AN. A two kind, three layer film wastried to be prepared in the same manner as in Example 1N by using theiron base oxygen-absorbing resin composition AN for a core layer, butirregularities of the iron powder were generated on a film surface, andthe good film was not obtained. Accordingly, the iron baseoxygen-absorbing resin composition AN was extruded and laminated as anoxygen-absorbing layer in a thickness of 30 μm on PP having a thicknessof 40 μm to obtain a laminated film in which an oxygen-absorbing layerwas subjected to corona discharge treatment. The above laminated filmwas laminated with a PET film and an aluminum-deposited PET film in thesame manner as in Example 1N to obtain an oxygen-absorbing multilayerfilm of a PET film (12)/adhesive (3)/aluminum-deposited PET film(12)/adhesive (3)/iron base oxygen-absorbing resin composition AN(30)/PP (40). Numerals in parentheses mean a thickness (unit: μm) of therespective layers. Then, a three side-sealed bag was prepared in thesame manner as in Example 1N, and a storing test thereof was carried outwithout allowing water to be present in the film to find that an oxygenconcentration in the bag was not sufficiently lowered. Further, it wasdifficult to confirm the content from an outside of the bag, andtherefore the bag was opened, and the content was confirmed to find thatit was discolored.

Example 9N

A four kind, six layer multilayer blow molding apparatus comprisingfirst to fourth extruding equipments, a die head and a metal die wasused to extrude components from the respective extruding equipments,wherein extruded were PP from the first extruding equipment, theoxygen-absorbing resin composition A described above from the secondextruding equipment, an ethylene-vinyl alcohol copolymer (product name:“Eval F101B” manufactured by Kuraray Co., Ltd.) from the third extrudingequipment and a polypropylene base adhesive resin (product name: ModecAP P604V manufactured by Mitsubishi Chemical Corporation) from thefourth extruding equipment, whereby prepared was an oxygen-absorbingmultilayer bottle which comprised PP/oxygen-absorbing resin compositionA layer/adhesive layer/ethylene-vinyl alcohol copolymer/adhesivelayer/PP (weight ratio (%) of the respective layers: 15/15/3/6/3/58))from an inside and which had a content volume of 300 mL and a thicknessof 300 μm in a thinnest wall part of a barrel part. The oxygen-absorbingmultilayer bottle was a multilayer bottle which was free from thicknessunevenness and the like and had a good appearance.

Next, the multilayer bottle thus obtained was charged under nitrogensubstitution with 300 mL of the amino acid preparation model liquid usedin Example 1N. A nitrogen substitution rate in the bottle was 95%. Then,the bottle was stored at 40° C. and 90% RH, and an appearance of thecontent after 6 months was confirmed to find that it was not changed.

The present invention relates to a method for preserving a content of afluid infusion container in which a content of a fluid infusioncontainer is preserved in an oxygen-absorbing container prepared byusing wholly or partially an oxygen-absorbing multilayer film preparedby laminating at least three layers of an oxygen-permeating layercomprising a thermoplastic resin, an oxygen-absorbing resin layercontaining at least a polyolefin resin, a transition metal catalyst anda polyamide resin and a gas-barriering layer comprising a gas-barrieringfilm in order from an inside. A content of the fluid infusion containercan be preserved for a long time without being deteriorated. Further,the above oxygen-absorbing multilayer film has a transparency.

1. An oxygen-absorbing resin composition containing a polyolefin resin,a transition metal catalyst and a polyamide resin obtained bypolycondensation of aromatic diamine and dicarboxylic acid, wherein anend amino group concentration of the above polyamide resin is 30 μeq/gor less, and a total content of the transition metal catalyst and thepolyamide resin is 15 to 60% by weight based on a whole amount of theoxygen-absorbing resin composition.
 2. An oxygen-absorbing multilayerfilm comprising at least three layers of a sealant layer comprising athermoplastic resin, an oxygen-absorbing resin layer containing apolyolefin resin, a transition metal catalyst and a polyamide resin anda gas-barriering layer comprising a gas-barriering film, wherein theabove polyamide resin is a polyamide resin which is obtained bypolycondensation of aromatic diamine and dicarboxylic acid and in whichan end amino group concentration is 30 μeq/g or less, and a totalcontent of the transition metal catalyst and the polyamide resin in theoxygen-absorbing resin layer is 15 to 60% by weight.
 3. Theoxygen-absorbing resin composition according to claim 1, wherein thearomatic diamine is at least one selected from metaxylylenediamine andparaxylylenediamine, and the dicarboxylic acid is at least one selectedfrom adipic acid, sebacic acid and isophthalic acid.
 4. Theoxygen-absorbing resin composition according to claim 1, wherein thedicarboxylic acid contains adipic acid and sebacic acid in a proportionof 3/7 to 7/3 in terms of a mole ratio (adipic acid/sebacic acid), andthe aromatic diamine contains metaxylylenediamine in a proportion of0.985 to 0.997 mole based on 1 mole of the dicarboxylic acid.
 5. Theoxygen-absorbing resin composition according to claim 1, wherein thepolyamide resin is prepared by subjecting at least three components ofmetaxylylenediamine, adipic acid and isophthalic acid topolycondensation in a mole ratio of metaxylylenediamine:adipicacid:isophthalic acid=0.985 to 0.997:0.70 to 0.97:0.30 to 0.03
 6. Aproduction process for the oxygen-absorbing resin composition accordingto claim 1 in which a content of the transition metal is 200 to 5000 ppmbased on the polyolefin resin, wherein a master batch containing thepolyolefin resin and the transition metal catalyst is molten and kneadedwith the polyamide resin.
 7. An oxygen-absorbing multilayer containerprepared by thermoforming the oxygen-absorbing multilayer film accordingto claim
 2. 8. An oxygen-absorbing multilayer container prepared bysubjecting a laminated material prepared by laminating at least a papersubstrate, a gas-barriering layer, the oxygen-absorbing resin layeraccording to claim 2 and a thermoplastic resin inner layer in this orderto container manufacturing.
 9. A method for preserving a content of afluid infusion container in which a content of a fluid infusioncontainer is preserved in an oxygen-absorbing container prepared byusing wholly or partially an oxygen-absorbing multilayer film preparedby laminating at least three layers of an oxygen-permeating layercomprising a thermoplastic resin, an oxygen-absorbing resin layercontaining at least a polyolefin resin, a transition metal catalyst anda polyamide resin and a gas-barriering layer comprising a gas-barrieringfilm in order from an inside, wherein the above polyamide resin is apolyamide resin which is obtained by polycondensation of at leastaromatic diamine and dicarboxylic acid and in which an end amino groupconcentration is 30 μeq/g or less, and a total content of the transitionmetal catalyst and the polyamide resin in the oxygen-absorbing resinlayer is 15 to 60% by weight.
 10. The oxygen-absorbing resin compositionaccording to claim 3, wherein the dicarboxylic acid contains adipic acidand sebacic acid in a proportion of 3/7 to 7/3 in terms of a mole ratio(adipic acid/sebacic acid), and the aromatic diamine containsmetaxylylenediamine in a proportion of 0.985 to 0.997 mole based on 1mole of the dicarboxylic acid.
 11. The oxygen-absorbing resincomposition according to claim 3, wherein the polyamide resin isprepared by subjecting at least three components of metaxylylenediamine,adipic acid and isophthalic acid to polycondensation in a mole ratio ofmetaxylylenediamine:adipic acid:isophthalic acid=0.985 to 0.997:0.70 to0.97:0.30 to 0.03.
 12. The oxygen-absorbing resin composition accordingto claim 4, wherein the polyamide resin is prepared by subjecting atleast three components of metaxylylenediamine, adipic acid andisophthalic acid to polycondensation in a mole ratio ofmetaxylylenediamine:adipic acid:isophthalic acid=0.985 to 0.997:0.70 to0.97:0.30 to 0.03
 13. The oxygen-absorbing resin composition accordingto claim 10, wherein the polyamide resin is prepared by subjecting atleast three components of metaxylylenediamine, adipic acid andisophthalic acid to polycondensation in a mole ratio ofmetaxylylenediamine:adipic acid:isophthalic acid=0.985 to 0.997:0.70 to0.97:0.30 to 0.03
 14. A production process for the oxygen-absorbingresin composition according to claim 3 in which a content of thetransition metal is 200 to 5000 ppm based on the polyolefin resin,wherein a master batch containing the polyolefin resin and thetransition metal catalyst is molten and kneaded with the polyamideresin.
 15. A production process for the oxygen-absorbing resincomposition according to claim 4 in which a content of the transitionmetal is 200 to 5000 ppm based on the polyolefin resin, wherein a masterbatch containing the polyolefin resin and the transition metal catalystis molten and kneaded with the polyamide resin.
 16. A production processfor the oxygen-absorbing resin composition according to claim 5 in whicha content of the transition metal is 200 to 5000 ppm based on thepolyolefin resin, wherein a master batch containing the polyolefin resinand the transition metal catalyst is molten and kneaded with thepolyamide resin.
 17. A production process for the oxygen-absorbing resincomposition according to claim 10 in which a content of the transitionmetal is 200 to 5000 ppm based on the polyolefin resin, wherein a masterbatch containing the polyolefin resin and the transition metal catalystis molten and kneaded with the polyamide resin.
 18. A production processfor the oxygen-absorbing resin composition according to claim 11 inwhich a content of the transition metal is 200 to 5000 ppm based on thepolyolefin resin, wherein a master batch containing the polyolefin resinand the transition metal catalyst is molten and kneaded with thepolyamide resin.
 19. A production process for the oxygen-absorbing resincomposition according to claim 12 in which a content of the transitionmetal is 200 to 5000 ppm based on the polyolefin resin, wherein a masterbatch containing the polyolefin resin and the transition metal catalystis molten and kneaded with the polyamide resin.
 20. A production processfor the oxygen-absorbing resin composition according to claim 13 inwhich a content of the transition metal is 200 to 5000 ppm based on thepolyolefin resin, wherein a master batch containing the polyolefin resinand the transition metal catalyst is molten and kneaded with thepolyamide resin.